When presented with allegations about the Badr Airlines cargo, the Sudanese Foreign Ministry told the U.S. that the flights "were limited to carrying farm equipment and equipment for non-military manufacturing."
Not so helpful neighbor
In his last years in power, Egyptian President Hosni Mubarak became viscerally hostile to growing Iranian influence in the region.
After the last conflict in Gaza in January 2009, Israeli officials noted that Egypt had played a positive role by keeping the Rafah border closed, choking off supplies to Gaza, which was (and is) already subject to a maritime blockade.
Netanyahu then said he "looked forward" to working with the Egyptians to further blunt Hamas' capabilities, and it seemed he had a willing partner.
Egypt increased military patrols -- on the ground and in the air -- along its border with Sudan. Egyptian intelligence officials told U.S. diplomats that they had prevented Iran from transferring money to Gaza to pay the salaries of fighters for Hamas' military wing.
But according to a cable sent in April 2009 from the U.S. embassy in Cairo, longtime Egyptian intelligence chief Omar Suleiman told the chairman of the U.S. Joint Chiefs of Staff, Adm. Mike Mullen, that Iran was trying to recruit support from Sinai Bedouin tribes to facilitate arms smuggling to Gaza.
A U.S. cable sent from the Cairo embassy three months later said Mubarak's view was that "the immediate threat to Egypt comes from Iranian conspiracies with Hamas (which he sees as the "brother" of his own most dangerous internal political threat, the Muslim Brotherhood) to stir up unrest in Gaza, but he is also concerned about Iranian machinations in Sudan."
Mubarak is now long gone, and the Muslim Brotherhood is in power in Egypt. Since the latest conflict erupted, the Egyptian prime minister has visited Gaza to express solidarity with Hamas.
In addition, Sinai is largely beyond the reach of an enfeebled Egyptian state.
Sinai smugglers outwit security
"These weapons systems are being moved primarily by Sinai Bedouin criminal families. This is what they do," says Matthew Levitt of the Washington Institute for Near East Policy.
"To take them on is something that the central government in Egypt, the Morsy government, does not want to do and may not be all that capable of doing right now."
An Egyptian national security official, Usama Emam, told CNN Monday that Egypt was working hard to curb arms supplies from both Libya and Sudan.
"We have succeeded in the past months in obstructing truckloads of machine guns, anti-aircraft missiles and rockets that have passed through the Libyan border at the Saloum crossing," he said.
But he acknowledged that Sinai-based smugglers were formidable opponents.
"Bedouin have different tactics like releasing the air of the tires of their 4x4 trucks in order to counter the soft deep desert sand, as they avoid any highways," he said.
"There is no doubt that the disbanding of Mubarak's fierce state security has hindered the grip on Sinai and has given the Bedouin more freedom than ever," Emam added.
"Several months back we captured a human trafficker transporting African refugees from Sudan into Sinai; and he had hidden boxes of ammunition and Grad missiles in the same truck carrying the Africans who are sold to Bedouin in Sinai."
However, Menai, the Bedouin leader from the Swarke tribe, said the huge sums of money involved in the smuggling meant many officials could be bribed.
"Military intelligence officers stationed in North-Sinai turn a blind eye when it comes to the multimillion-dollar tunnel business, and many of them at different ranks receive bribes," he told CNN.
As the regional landscape changes, Iran has dropped a hint that it will not be deterred from flying its flag in the Red Sea. Within the past fortnight, two Iranian warships -- a helicopter carrier and destroyer -- visited Port Sudan for five days.
The visit supported "strong political, security and diplomatic relations." a Sudanese military spokesman said.
Acting U.S. State Department spokesman Mark Toner said: "It's hard for us to know what the details are of this visit right now... Certainly we would be concerned."
So were the Saudis. Port Sudan looks out on a vital shipping lane for Saudi crude oil exports.