Brent crude oil futures climbed back to positive territory and U.S. crude pared losses Thursday after reports from Saudi Arabia said police had fired upon protesters, traders and other market sources said.

By 1:45 p.m. EST, in London, April Brent crude rose 22 cents to $116.16 a barrel, trading from $113.52 to $116.55.

On the New York Mercantile Exchange, U.S. crude for April delivery was down 87 cents at $103.51 a barrel, having traded from $100.62 to $105.06.

Traders cited a report from the Associated Press that Saudi Arabian police had fired on protesters in the kingdom's east.

Earlier, oil prices had tumbled as the dollar strengthened on renewed Euro zone credit worries, but analysts said fears persisted that prolonged conflict in Libya could do long-lasting damage its oil infrastructure.

Oil prices were also pressured earlier by data showing that China, the world's second largest oil importer, unexpectedly posted the largest trade deficit in seven years, stirring global economic growth worries.

New U.S. jobless claims rose last week and the country's trade deficit widened in January, weighing further on U.S. crude.

(Additional reporting by Robert Gibbons in New York; Editing by Walter Bagley)