Thousands of Israeli invasion troops thrust deep into Lebanon Sunday to battle Palestinian guerrillas from the southern border region to towns near the capital of Beirut. Syria said its forces joined the fighting in a major escalation of the conflict.
'We are in a war situation,' an Israeli air force commander said at a base in Israel. 'We're succeeding in catching the terrorists no matter where they are and we are keeping them under fire.'
The lightning Israeli offensive, spearheaded by columns of tanks and naval, air and artillery bombardments, had by the evening reached the town of Damour, just 13 miles south of Beirut.
Palestine Liberation Organization sources said Israeli gunboats were pounding the coastal road outside Damour and that Israeli warplanes were flying low level missions over the town.
The PLO also said Israeli troops had made an amphibious landing north of the coastal city of Sidon, 22 miles south of the capital, and were fighting fierce battles with guerrillas.
'They are coming from everywhere,' a man shouted in Sidon as he and thousands of other civilians fled north to escape bombing by Israeli jet fighters. 'God help us,' yelled a woman fleeing with her children.
The long-expected invasion -- the second in four years -- came on the 15th anniversary of the 1967 Middle East war that Israel won in six days.
'Our morale is very high and our fighters will continue to fight until the last drop of their blood,' a PLO spokesman in Beirut vowed.
There were no immediate reports of casualties from either side, but a U.N. spokesman said one Norwegian soldier in the peacekeeping force in south Lebanon was killed when he was caught in a cross-fire.
Israeli troops battled the Palestinians in the streets of Tyre, 13 miles north of the border on the Mediterranean coast. Paratroopers landed by helicopter and boat in the towns of Ansar and Zahrani further to the north.
The PLO and U.N. sources said the guerrillas had slowed the advance of armored columns in the Tyre area. The fighting enveloped the city in a cloud of black smoke and terrified civilians poured into the Lebanese army barracks seeking protection.
In Damascus, the Syrian military command said contingents of its 25,000-man force occupying Lebanon were engaged in artillery duals with Israeli forces in an escalation of the conflict that could lead to the fifth full-scale Mideast war in 35 years.
'The invading Israeli forces in southern Lebanon have advanced toward our forces and, after taking up positions just facing our own, they began shelling our forces,' the Syrian statement said.
The statement said Syrian forces had been orderd to return the fire from Israeli forces near the southeastern villages of Hasbaya and Jarmaq.
'They have now been engaged since dusk in exchanges of shellfire,' a Syrian communique said.
Lebanese government sources said Syrian units were moving toward Nabatiyeh, a southern PLO center, possibly to reinforce a garrison five miles north of the town.
An Israeli military spokesman said there was 'no verification' of the clashes with Syrian troops.
Earlier, the Israeli air force commander said 'we're keeping our distance from the Syrians and avoiding all contact with them.' An Israeli spokesman said the Syrian force would not be attacked 'unless it attacks our forces.'
Palestinian sources placed the size of the Israeli force at 20,000 men, but Israel would provide no figures on its troop strength. Israeli military intelligence said there were about 6,000 guerrillas in the south.
A column of 100 Israeli tanks and armored personnel carriers pushed its way into Tyre, where it was reinforced by paratroopers landed by helicopters, a spokesman for the United Nations peacekeeping force in south Lebanon said.
Later, a U.N. force spokesman said 150 tanks and 170 armored personnel carriers were approaching Nabatiyeh, but it was not clear if they included forces from the Tyre area 18 miles to the southwest.
The spokesman said it was estimated three Israeli armored brigades and one mechanized infantry brigade -- about 14,000 men -- were heading toward Nabatiyeh.
Other Israeli troops crossed the border into eastern Lebanon and advanced on Nabatiyeh from the opposite direction, the U.N. officials said.
Israeli planes bombed the nearby guerrilla-held Crusader castle at Beaufort, the PLO's main observation post that is only about three miles from the Israeli border.
Lebanese officials said waves of Israeli warplanes bombed the coastal city of Sidon, 24 miles north of the border, and a major oil refinery at Zahrani, setting off a huge fire.
The PLO said its forces destroyed two Israeli warplanes, two helicopters, 42 tanks and 20 armored personnel carriers. It also claimed 150 Israeli casualties and said Israeli commandos were forced to retreat into their gunboats and abandon Zahrani 'after suffering unexpected fatalities and material losses.'
In Jerusalem, a military command statement said the 'Israeli Defense Forces today launched a search-and-destroy operation against sources of Palestinian fire and guerrilla concentrations which have been firing on Israeli villages for the past few days.'
The invasion followed two days of intense Israeli bombing raids of guerrilla positions in Lebanon that killed 210 and wounded 500 in retaliation for the shooting of the Israeli ambassador in Britain Thursday.
Israel released no details on the invasion, but admitted for the first time since the 1973 Mideast war that it had lost aircraft in combat -- one jet and one helicopter presumably shot down by Palestinian gunners.
The pilot of the Israeli jet parachuted and was taken prisoner by the PLO, an Israeli military communique said.
At the Western economic summit in Versailles, France, President Reagan called on Israel to withdraw its troops and sent veteran mediator Philip Habib to Israel with a personal appeal to Prime Minister Menachem Begin to stop the fighting. Israel rejected the request.
Reagan also ordered an immediate evacuation of non-essential American personnel from the U.S. Embassy in Beirut and appealed to Israeli Prime Minister Menachem Begin and all other parties in the Middle East to end the violence.
'Yes, we want them to withdraw,' said Secretary of State Alexander Haig, in Versailles with the president. 'We did not want them to go in in the first place.'
In Moscow, the official Soviet news agency Tass condemned the Israeli invasion, calling it a 'fifth war against the Arabs.' The agency accused the Israelis of coordinating the attacks with the United States.
Landing at Zahrani, 28 miles north of Israel on the Mediterranean coastal road, put the Israeli forces further north than the 1978 invasion.
The Litani river, which the Israelis crossed, is the northern limit of the U.N. peacekeeping buffer zone set up after the 1978 invasion and has also been unofficial southern border beyond which Israel has said it would not tolerate Syrian troops occupying Lebanon.
The Israelis withdrew their forces three months after invading, with casualties on both sides estimated at 2,000 dead. U.N. peacekeeping forces moved into the south but left a 150 square mile border enclave under the control of renegade Lebanese army Maj. Saad Haddad, who was allied with Israel.
The United Nations Security Council, which has called for a cease-fire, met privately to gauge the seriousness of the latest crisis.
U.N. Secretary-General Javier Perez de Cuellar, in a report to council members, said the U.N. peacekeeping forces in south Lebanon had been either bypassed or overrun by the Israeli troops.
The military council of the PLO, chaired by Yasser Arafat, held an urgent meeting in Beirut as the Israeli forces invaded.
In Washington, Israeli ambassador Moshe Arens said Israel had no plans to stay in south Lebanon, but said there would be no stability in the area until the PLO forces are removed from the area.
Israel dubbed the invasion 'Operation Peace for Galilee.'
Prime Minister Menachem Begin told Reagan in a letter that the 'army received an order to repulse the terrorists a distance of 28 miles north so that all our population in the Galilee will be free of the threat to their lives,' the state-run Israel Radio said.
'The government of Israel has decided to do its utmost to put an end to this intolerable situation.'
Israeli military sources said the Palestinians' longest range artillery pieces were 130-mm Soviet-made cannon with a range of 17 miles.
The Israeli military reported 26 guerrilla attacks or attempted attacks in May alone and 'hundreds' more over the past few months. Israel said the final provocation was the attack on the Israeli ambassador in Britain.
That set off a relentless Israeli air bombardment of Palestinian bases, which the guerrillas answered with constant Katyusha rocket and artillery fire on northern Israel that killed two people and wounded nine others.
In Cairo, Egyptian President Hosni Mubarak urged restraint both by Israel and the Palestinians.
'Egypt is calling for restraint and we are against the use of force against the Palestinians (in Lebanon) and and are also against its use against the other party (Israel),' Mubarak said.