Sudan's foreign ministry on Monday denied that Iran had any involvement in a military factory which Khartoum says was attacked by Israeli aircraft last week.
"The Ministry of Foreign Affairs confirms what is known by all: that Iran has no need to manufacture weapons in Sudan, for Iran or for its allies," the ministry said in a statement.
"We want to deny any relation between Sudan's military manufacturing and any foreign partner."
Sudan's links to Iran have come under scrutiny after Khartoum accused Israel of sending four radar-evading aircraft to strike the Yarmouk military factory in the heart of the capital at midnight last Tuesday.
Israeli officials have expressed concern about arms smuggling through Sudan and have long accused Khartoum of serving as a base of support for militants from the Islamist Hamas movement that rules the Gaza Strip.
Israel refused all comment on Khartoum's allegations about the factory blast.
But a top Israeli defence official, Amos Gilad, said last week that Sudan "serves as a route for the transfer, via Egyptian territory, of Iranian weapons to Hamas and Islamic Jihad terrorists."
Sudan's foreign ministry called Israel an "outlaw state... trying its best to pass fabricated information through different sources that have a link with Israel, in an effort to provide reasons for its aggression.
"This includes talk about claimed relations between the al-Yarmouk compound and Iran and Syria, and the Hamas Islamic struggle movement in Palestine, and Hezbollah in Lebanon."
Jonah Leff, of Small Arms Survey, a Swiss-based independent research project, said the project has documented the presence of a drone, landmines and other Iranian weapons in Sudan, but he thinks they were acquired directly from Iran rather than being locally manufactured.
"There's a lot of speculation that Iran has provided technical assistance to the Sudanese for their weapons manufacturing but I haven't been able to confirm that they're producing any Iranian weapons," he told AFP on Thursday.
Evidence from weapons packaging suggests that Chinese-origin arms and ammunition are exported to Yarmouk, Small Arms Survey says.
Information Minister Ahmed Bilal Osman told reporters that "traditional weapons" are made at the factory.
On a visit to Tehran last August, Sudanese President Omar al-Bashir described the relationship between Sudan and Iran as "deeply rooted."
Two Iranian navy ships, the helicopter carrier Kharg and destroyer Admiral Naqdi, arrived at Sudan's Red Sea port on Monday, Iran's Press TV reported.
The ships were sent to the Djibouti area in September, Press TV said, adding that the commanders would meet their Sudanese navy counterparts during their visit.
In April last year, Sudan said it had irrefutable evidence that Israeli attack helicopters carried out a strike on a car in Red Sea state.
That incident mirrored a similar attack by foreign aircraft on a truck convoy reportedly laden with weapons in eastern Sudan in January 2009.
Fire erupted again late on Monday at the Yarmouk site.
"There is no new attack but the fire broke out again. It began in some places not tended by firemen before," Sawarmi Khaled Saad, the Sudanese army spokesman, was quoted as saying by the official SUNA news agency.
Residents of the area told AFP they saw smoke and fire in the area.