Lagos, Nigeria ? Militants threatened more attacks on Nigeria’s oil facilities and vowed Sunday to cut daily oil exports by 1 million barrels, adding to concerns for OPEC as it prepares for a strategy meeting this week.

Oil is already more $60 a barrel, and the markets are nervous about potential disruptions to the supply from this OPEC member, which is African’s largest producer of crude oil.

A.F. Alhajji, an energy analyst in the United States, said the Organization of Petroleum Exporting Countries was unlikely to trim the cartel’s overall output when it meets Wednesday because of worries about the unrest in Nigeria’s oil region and Iraq’s crippled production.

In attacks on Nigerian pipelines and oil facilities, the Movement for the Emancipation of the Niger Delta has reduced the country’s production by 455,000 barrels a day. Nigeria normally exports 2.5 million barrels daily.

The group claims to be fighting for the interests of Niger Delta’s people, who remain impoverished while the Nigerian government benefits from the region’s oil wealth. The group threatens to escalate the conflict by attacking international oil tankers in Nigerian waters.