Oil prices leapt more than $1 this morning after Nigerian militants crippled production and threatened more violence in the world's eighth-largest exporter.
North Sea Brent crude futures were up $1.26 at $61.15 a barrel by 6.36am, rallying for a third day after hitting a one-and-a-half month low last Wednesday. Brent, which rarely trades actively during Asian hours, rose $1.10 on Friday.
The New York Mercantile Exchange, which normally sets price direction, was closed for the US Presidents Day holiday.
More gains were expected once European traders assessed the damage of a fresh surge in violence against Nigeria's oil industry, which has yet to fully recover from a series of attacks and kidnappings a month ago.
The closure includes 106,000 bpd of output that has been shut since an earlier attack in January.
The Movement for the Emancipation of the Niger Delta, responsible for attacks seen linked to presidential elections in April 2007, warned of more violence and threatened to blow up oil tankers.
"Oil workers on any kind of vessel should leave the vicinity of Delta state immediately," the group said in an e-mail. The group continued its campaign of sabotage today, blowing up a military houseboat and an oil pipeline manifold.
Escalating fighting between Nigerian government forces and militants on Friday had lifted prices, extending a rebound from a nearly three-week, $10-plus slump.