Sudanese opposition groups claim the Khartoum regime, which has long maintained links with the Islamic Republic, is allowing Iran to establish a naval base on its coastline along the western shore of the Red Sea.
Israel allegedly mounted an Oct. 24 airstrike against the Yarmouk arms plant outside Khartoum, a plant some sources maintain was producing Iranian missiles to be smuggled through Egypt to Palestinian militants in the Gaza Strip.
Israel has long conducted intelligence-gathering operations in Eritrea, on the eastern shore of the Red Sea where Tehran seeks to control the strategic Bab el-Mandeb Strait at the southern end of the waterway.
Eritrea, an economically weak state with a population of 5.2 million, broke away from Ethiopia in 1991 after a long and bloody independence war. It's had a security problem ever since because Ethiopia, with 90 million people, lost its ports on the Red Sea and became landlocked.
Eritrea's greatest fear is an invasion by U.S.-backed Ethiopia to recover its lost territory. The countries fought a fierce border war in 1998-2000 and relations remain tense.
This has made Eritrea, isolated from its African neighbors and the United States, open to outside alignments and being dragged into other conflicts.
"In exchange for resources, possibly including modest amounts of cash and weapons, Eritrea has exhibited a willingness to become a base of support for Middle Eastern powers that want to exert greater influence in the Horn of Africa," the U.S. global security consultancy Stratfor observed.
"As a result, Eritrea and its waters in the Gulf of Aden have become another venue for Iran and Israel's rivalry.
"Israel and Iran's engagement with Eritrea is an extension of their rivalry over the Red Sea, which allegedly led to the bombing of the Yarmouk weapons factory in Sudan," Stratfor noted.
"Iran's operations in Eritrea are relevant to Tehran's larger goal of controlling the Bab el-Mandab Strait and the water route to the Suez Canal."
Iran is seeking to build up its naval forces and extend operations beyond the Persian Gulf to the Indian Ocean, the Red Sea and even the Mediterranean.
In the last few months Tehran has twice sent warships to Sudan's main Red Sea port to fly the flag and demonstrate support for the crisis-battered regime of President Omar al-Bashir.
It's locked in an explosive dispute with the infant state of South Sudan, which became independent in July 2011 after a decades-long civil war and gripped by growing unrest.
The South has the bulk of Sudan's oil reserves, the loss of which has cost Khartoum dearly and seriously undermined Bashir's oppressive regime.
Israel supported the southern rebels during the civil war against the Muslim Arab regime in Khartoum, primarily to contain Egypt and Iranian expansion on the Jewish state's western flank.
These days, Israel's widely suspected of aiding the fledgling state in the south against Khartoum.
In November, Sudan reported it thwarted a coup plot involving senior figures close to Bashir. Few details have been disclosed but there are deep suspicions Israel may have had a hand in it.
Increasingly, Israel's primary objective is to block Iranian operations and arms shipments in Sudan. The weapons are mainly shipped by the Revolutionary Guards from their Bandar Abbas base in the Persian Gulf to southern Sudan from where they are moved north overland to Egypt and across the Sinai Peninsula to Gaza.
The heavy Nov. 14-21 clashes between Israel and Hamas militants were triggered by Israel's alarm at the buildup in Gaza of Iranian Fajr missiles, capable of reaching Israel's population centers.
Indeed, during the fighting, several Fajrs were fired at Tel Aviv, and another at Jerusalem, a nightmare scenario the Israelis have long dreaded.
The missiles were shot down but the Israelis can be expected to pull out all the stops to prevent a much more destructive onslaught from Gaza, along with Hezbollah in Lebanon.
Israeli warplanes and unmanned aerial vehicles reportedly wiped out at least two arms shipments being trucked through Sudan in 2010.