Two men suspected to be among the abductors of four foreign oil workers in southern Nigeria have been arrested by security agents, Nigerian media reported on Tuesday.

The men were nabbed weekend after the State Security Service ( SSS) mounted a tight surveillance in the Niger Delta, where the majority of Nigeria's oil is produced, since the abduction on January 11.

Nigeria's Vanguard newspaper quoted a source close to the SSS as saying that if the kidnappers did not release the hostages in the next few days, security agents might be forced to return fire for fire.

"We are only awaiting clearance from the presidency, which had ordered that we should not use force. Once that is cleared, we will launch attack on them wherever they are. They cannot hold the country to ransom," the source said.

The four hostages, an American, a Briton, a Bulgarian and a Honduran, who were working for Shell's subcontractors, were seized on January 11 from an offshore oil field operated by Shell.

There is confusion over different reports about the demand of the kidnappers with one of the groups saying it wanted a ransom. Another group dismissed the suggestion and instated that former governor Diepreye Alamieyeseigha of Bayelsa, who were impeached and arrested last month for corruption, and a local militia leader be released immediately.

The kidnapping and a spate of attacks on Shell's facilities in the last one month have cut Nigeria's production by 211,000 barrels, or about 9 percent of the country's total output.

Source: Xinhua