Iranian naval vessels docked in Port Sudan on 30 October just over a week after explosions demolished an arms factory in Khartoum.
Sudan has accused Israel of bombing the factory and the arrival of Iranian vessels in Sudan is causing concern that tension between the two Middle Eastern countries is growing.
Tehran has viewed the Arab-led Sudan as a key African ally. Israel fears that arms are being smuggled from Iran through Sudan into Egypt. and then into the Gaza strip.
Israel has established itself as a military ally with South Sudan since the country secured its independence last year.