One of the main armed groups operating in Nigeria's oil rich delta, The Movement for the Emancipation of the Niger Delta, or MEND, has released a statement calling an end to a four-month ceasefire on attacks and kidnappings of expatriates. The statement follows unconfirmed reports that a leading figure in MEND was earlier this month arrested in Angola on arms trafficking charges. For VOA, Sarah Simpson has more from Lagos.

The statement, released in an e-mail by MEND Sunday, warned of a resumption of attacks on Nigeria's multi-billion dollar oil industry.

"With effect from 12 midnight today, Sunday 23, 2007, we will commence attacks on installations and abduction of expatriates," the statement read.

Attacks will come without warning, though MEND will release a statement confirming their involvement soon after, the e-mail said.

Previous MEND warnings have resulted in bombings of oil facilities and abductions of foreigner workers that cut Nigeria's oil production by up to 25 percent from the past two years and forced up oil prices worldwide.

The statement also refuted recent reports that 'Jomo Gbomo' - the pseudonym for MEND's mysterious spokesperson - was arrested earlier this month in Angola for gun running.

Nigerian police spokesman Haz Iwendi told VOA he could not confirm the reports of Jomo Gbomo's arrest.

No reporter has ever knowingly met Jomo Gbomo, whose sole means of communicating with journalists is by e-mail.

MEND and other militant groups in the region are seeking a greater share of the region's oil wealth. Most Niger Delta residents are impoverished, despite the billions of dollars the government and oil companies reap from oil production.

Their campaign of bombings and abductions of expatriate workers operating in the delta was suspended as new President Umaru Yar'Adua took office in May. MEND said the cessation of hostilities was to facilitate dialogue.

Four months later, MEND accuses President Yar'Adua's government of failing to address the problems in the delta and attacks will resume.

"We will not sit back and allow our birth right to be exchanged for a bowl of porridge," said MEND's latest e-mail.

President Yar'Adua is currently in the United States for the opening of the U.N. General Assembly in New York. President Yar'Adua has repeatedly said finding a solution to the violence that has left scores of military, militants and civilians dead in the Niger Delta is a priority for his administration.