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Nigeria's main militant group declared a unilateral cease-fire Sunday, saying elders in the restive southern region had asked the fighters to allow peace efforts to proceed. The Movement for the Emancipation of the Niger Delta said that it would halt attacks starting at midnight Tuesday. The group has been behind two years of crippling attacks on Nigeria's oil infrastructure that have sliced about one-quarter of Nigeria's daily oil output, helping push up crude prices in international markets.

The average price of regular gasoline at self-serve stations nationwide was $4.10 a gallon on Friday, up 10 cents from two weeks ago and $1.10 from a year ago, according to the Lundberg Survey of 7,000 gas stations.

Sen. Barack Obama said that as president, he would strengthen government oversight of energy traders he blames in large part for the skyrocketing price of oil. The Democratic candidate's campaign singled out the "Enron loophole" for allowing speculators to run up the cost of fuel by operating outside federal regulation.

Obama's campaign blamed the loophole on former Sen. Phil Gramm, R-Texas, who serves as GOP candidate John McCain's co-chairman and economic adviser. The Obama campaign accused Gramm of inserting a provision into a bill in late 2000 "at the behest of Enron lobbyists" that exempted some energy traders from government oversight.

Gramm said he had "nothing to do with the writing of the provision." And McCain spokesman Tucker Bonds said McCain has supported efforts to close the loophole and noted the bill in question was signed into law by former President Bill Clinton.

Congress already has acted to close the loophole, including a provision in the farm bill that passed earlier this year. But Obama's campaign said he would go further by requiring that U.S. energy futures be traded on regulated exchanges.

ASSOCIATED PRESS