Two Iranian warships docked in Sudan on Saturday in the second port call by the Iranian navy in Sudan in a little over a month.
The visit risks widening divisions inside the Sudanese government and upsetting the African country's Gulf Arab donors, as ties between Sudan and Iran have come under increased scrutiny in recent weeks.
Two Iranian navy ships also visited in October, days after Sudan accused Israel of bombing a weapons factory in the capital Khartoum. Israel declined to comment on the alleged attack but has accused Sudan of smuggling weapons to the Gaza Strip, which is ruled by the Iranian-allied Palestinian movement Hamas.
Israeli officials fear Iran will continue arming terrorist organizations in Gaza, especially with medium-range rockets, despite the truce with Hamas that brought an end to the eight days of fighting of Operation Pillar of Defense. In the past two years, several Fajr-5 rockets, which have a range of 75 kilometers, have made their way from Iran to Gaza via Sudan and Egypt. Hamas and Islamic Jihad have also used Iranian know-how to manufacture 200-millimeter rockets in Gaza. Those have a range of 80 kilometers or more.
The Sudanese army described the docking of two more warships in Port Sudan on Saturday as a routine visit to refuel. But analysts say it could hinder Sudan's efforts to win badly needed aid from Gulf Arab oil producers such as Saudi Arabia, which are worried about Iran's influence in the region.
President Omar Hassan Bashir has held on to power in Sudan for 23 years, but an economic crisis has fuelled popular dissent and squeezed the patronage system that secures the loyalty of key figures in the army and ruling party. Last month, authorities arrested a former spy chief and 12 others accused of a coup attempt.
Faced with the loss of three-quarters of oil production when South Sudan broke away to become independent last year, Sudan's foreign ministry has sought to bolster ties with Gulf states.
But Sudan's military ties with Shi'ite power Iran are unnerving Sunni Muslim power Saudi Arabia, located just across the Red Sea from Port Sudan.
"Sudan needs to understand that this visit will not be accepted by Saudi Arabia," said Khalid al-Dakhil, a Saudi political analyst.
The kingdom has not publicly commented on the Iranian ship visits but pro-government newspaper al-Riyadh said Sudan was risking ties with the Gulf.
"Sudan is in a state of losing balance as it loses Arab friendship, especially of Gulf Arab states, who know the precise details of its alliance with Iran, politically and militarily," the daily wrote in an editorial titled "The masks fall between Sudan and Iran".
Bashir and Iran's President Mahmoud Ahmadinejad have met several times in the past two years but the bilateral ties are controversial inside the Khartoum government.
Analysts say the army, facing several insurgencies in Sudan's borderlands, wants to foster ties with Iran after both countries signed a military agreement in 2008.
"Iran is one of the few countries apart from China which would probably sell Sudan weapons," said Magdi El Gizouli, a fellow at the Rift Valley Institute which focuses on East Africa.
But the foreign ministry sees the Iranian connection as an obstacle to winning more investment from Gulf states and also Europe, trying to overcome Sudan's isolation and image as radical Islamist state.
Foreign Minister Ali Ahmed Karti sought to play down the visit of the ships. "This is normal cooperation between armies," he said on Tuesday, adding that a U.S. warship had docked in Port Sudan in October.
But in a television interview, reported by the Paris-based Sudan Tribune online newspaper, Karti said in November he had not been consulted over the first navy visit after opposing a similar docking in February.
"You have here a conflict of moderate forces who want to break the isolation and hardliners in the army who don't care about the West. They think wooing the West is a lost cause so they focus on Iran and Hamas," one Western diplomat said.
Despite the military ties, Iran and Sudan have little bilateral trade. Iran funds a bridge project in Khartoum, a cultural centre offers Farsi lessons and the state oil company has an office - otherwise Iran is hardly noticed in Khartoum.
That contrasts with Gulf states, which are among the biggest investors in the country and have just funded a large sugar plant and Sudan's only shopping mall. Diplomats say Sudan's central bank has toured the Gulf several times, trying to drum up support for more funding.
Want to enjoy 'Zen' reading - with no ads and just the article? Subscribe todaySubscribe now