A top militant leader said that armed groups in Nigeria 's restive south will halt attacks on oil-installations to give the new government a chance to deal with the region's problems.
But he warned there would not be an immediate end to the seizure of foreign workers.
Mujahid Dokubo-Asari was freed last Thursday after 18 months in prison on treason-related charges, a move widely seen as an attempt by new President Umaru Yar'Adua to meet a key demand of Niger Delta militants whose attacks on the country's energy industry have helped drive up global oil prices.
Dokubo-Asari said the inauguration of Vice President Goodluck Jonanthan, from the oil region's dominant ethnic Ijaw group, had added pressure in the region to give the government a chance to deal with the Niger Delta's lack of development.
"The majority of the Ijaw people are saying we should give Jonathan a chance, and we'll give him a chance," Dokubo-Asari told reporters. "We'll halt attacks."
But he warned: "If he fails us we'll resume the struggle."
Dokubo-Asari is leader of the Niger Delta People's Volunteer Force, which campaigned for local control of oil wealth in the impoverished oil region and fought battles with government troops around the oil industry center of Port Harcourt.
Dokubo-Asari's threat in Sept. 2004 to declare all-out war against Western oil companies pumping Nigeria's oil helped lift oil prices beyond US$50 for the first time.
He later agreed to disarm in favor of a peaceful campaign after talks with former president Olusegun Obasanjo. Dokubo-Asari was arrested and charged in Nov. 2005 after saying in a newspaper interview he would work for the break up of Nigeria.
Violence in the region escalated with Dokubo-Asari's arrest, spearheaded by a new group named Movement for the Emancipation of the Niger Delta, or MEND, which made Dokubo-Asari's release a prime objective. Dokubo-Asari is presumed to be powerful within MEND, which comprises various allied armed gang members, including many of Dokubo-Asari's fighters.
In the past 18 months the attacks have cut nearly a third of Nigeria's daily exports normally 3 million barrels and resulted in loss of billions of dollars in oil revenue.
But Dokubo-Asari warned it will take some time to bring under control the spate of hostage-takings that has seen more than 200 foreigners seized in the oil-rich delta since late 2005.
Many of the armed groups who have made money from ransom payments will be reluctant to give up what has become a very lucrative activity, he said.
"We can't stop this kidnapping immediately because many people are enjoying the money. It may take six months to one year to end it," Dokubo-Asari said.
Nigeria is Africa's leading oil producer and the number three exporter to the United States.
Yar'Adua, who took office at the end of May to succeed Obasanjo who completed his mandatory two terms, pledged that resolving the Niger Delta problem would be a major priority of his government.
Dokubo-Asari says for Yar'Adua to succeed he needs to call "a sovereign national conference" of the ethnic and interest groups in the country. The conference will to fashion a new constitution to give greater control of oil resources to the inhabitants of the delta and replace the current one imposed by departing military rulers in 1999, he said.