India attacked Pakistan by land and air today, claiming the capture of six towns in East Pakistan, launching heavy air raids on bases in West Pakistan and establishing an air and sea blockade to cut communications between the two parts of the country.
Pakistan President Agha Mohammad Yahya Khan told his people in a nationwide broadcast that the two countries were at war.
Heavy ground fighting was also reported at two places along the border between India and West Pakistan, which is separated from East Pakistan by 1,000 miles of Indian territory.
Each country charged the other with aggression.
China accused India with aggression and pledged its support for Pakistan.
Acting Foreign Minister Chi Pen-fei told a reception in Peking that "China will resolutely support the Pakistan Government and people in their struggle against the Indian aggression."
India's Prime Minister Indira Gandhi told her Parliament that Pakistan had declared war. She presented a "defense of India" bill to assume emergency powers for her government.
Indian Defense Secretary K. B. Lall said in New Delhi that Indian Air Force planes are carrying out massive retaliatory raids in both East and West Pakistan. The military commander in Calcutta said planes had bombed strategic installations in cities and towns inside East Pakistan, including_Dacca and Chittagong.
Indian Defense Minister Jagjivan Ram reported the latest details on the fighting between the two countries after India ordered her troops to move into East Pakistan and establish contact with the Muktii Bahini rebels there who have been fighting against West Pakistani Government troops.
An Indian defense ministry spokesman said that Indian Hunter fighters swept over a military airfield near Karachi, the main city of West Pakistan, and destroyed nine planes on the ground.
He said that brought to 33 the number of Pakistani aircraft shot down or destroyed on the ground since the large-scale fighting between the two countries began yesterday. The Indian spokesman said 11 Indian planes had been lost.
Ram told Parliament that Indian troops in West Pakistan reported knocking out six tanks and inflicting heavy losses on Pakistani units attacking along the cease-fire line established by the United Nations in Kashmir near the town of Akhnur. He said the Indians took losses of their own and were pushed back by Pakistani troops further south.
In East Pakistan, Ram said. Indian troops had captured the town and airfield at Shamshernagar in the northeast; the town. of Saigon and Majlispur, less than 60 miles from the East Pakistani capital of Dacca, in the east, and the towns of Thakurgaon, Darsana and Gazipur in the west.
Lall told Kaylor 10 Pakistani aircraft were shot down and three others probably destroyed in ground and air action in both East and West Pakistan.
Radio Pakistan said its Air Force had destroyed "26 Indian airplanes in both East and West Pakistan in air combat and by ground fire" and had attacked Indian bases today in addition to the 12 reported bombed or strafed yesterday.
Political informants close to the Indian cabinet said today the government is edging toward possible recognition of the Bangla Desh rebel government in East Pakistan.
India openly has supported the rebel Bangla Desh (Bengal Land) government exiled in Calcutta. The rebel government declared its independence from Pakistan March 26 and since has been fighting politically and in battle for autonomy from Yahya's military government at Islamabad, West Pakistan, more than 1,000 miles to the west.
President Yahya in a Pakistan Radio broadcast in Karachi said today his country is at war with India.
"It has always been India's hope and ambition to weaken Pakistan and crush it;" Yahya said. "India's latest and massive attack will be the last and the biggest war with Pakistan. We have tolerated enough.
"Tell the enemy that every Pakistani is ready to die for his country."
But in New Delhi, Foreign Secretary T. N. Kaul said, "India has not declared war on Pakistan. However. we are going to take moves in our self-defense to protect our territorial integrity. India reserves the right of taking any action that is necessary or right to safeguard her own security and integrity and to stop the oppression in Bangla Desh."
The statement was seen as a clear indication that India intends to push offensive action in East Pakistan until the area is under full control of the rebel movement that has been fighting the civil war for independence for eight months.
It is the third time the two neighbors have been at war. The first was in 1947-48 and the second, primarily in the western sector of Kashmir, in 1965.