Updated

Artillery rockets like those often used by insurgents in Afghanistan filled an illegal arms shipment intercepted at Nigeria's busiest cargo port, raising security questions about the oil-rich nation before its upcoming presidential election.

Officials allowed journalists on Wednesday to see the 107 mm rockets, rifle rounds and other weapons seized at Apapa Port. Authorities also said the shipment contained grenades, explosives, mortars and possibly rocket launchers. However, journalists visiting the holding yard Wednesday just inside of the port's main gate did not see those weapons.

Nigerian National Security Adviser Andrew Owoye Azazi declined to say what ship carried the weapons into the port, nor where they were heading. He also did not say whether other illegal arms had successfully passed through the chaotic ports.

"Let's not jump to conclusions," Azazi told journalists after viewing the weaponry.

Authorities said the weapons were in a shipment whose manifest labeled the goods as building materials. As officials opened new containers, they pulled away yellow insulation and plastic to reach the individual crates.

The seizure is a troubling sign in Africa's most populous nation, coming less than a month after a car bombing targeting the country's independence celebrations killed at least 12 people. With Nigeria approaching what could be a hotly contested presidential election next year, the nation continutes to see targeted killings allegedly committed by a radical Islamic sect and the threat of new violence in its oil-rich southern delta.

The shipment also raised questions about the possible involvement of former militant and alleged arms dealer Henry Okah. Okah faces terrorism charges in South Africa after authorities say he masterminded the Oct. 1 bombing and served as the de facto voice of the Movement for the Emancipation of the Niger Delta, or MEND, the oil-rich region's main militant group.

Okah has denied the charges and has said he did not write MEND communiques under the nom de guerre of Jomo Gbomo.