Oil prices fell on Friday April 12, 2012 and headed for a weekly loss after data showed that first-quarter economic growth in China, the world's No. 2 oil consumer, was the weakest in nearly three years, reinforcing concerns about slowing demand for petroleum.

A stronger dollar and a slip in U.S. consumer confidence in April also pressured oil prices.

Caution ahead of talks between Iran and five permanent members of the U.N. Security Council plus Germany about Tehran's disputed nuclear program, and news of falling North Sea oil production, were expected to limit losses heading into the weekend.

"The Chinese numbers were a little bit disappointing ... (but) we're not heading into a new substantial downward trend," said Tony Machacek, an oil futures broker at Jefferies Bache Ltd. "There's still quite a few geopolitical issues knocking about."

Expiring May Brent crude fell 43 cents to $121.28 a barrel by 12:12 p.m. EDT (1612 GMT), after dropping as low as $120.77. Brent crude for June delivery slipped 58 cents to $120.94.

U.S. May crude fell 60 cents to $103.04, having traded from $102.61 to $103.90. Prices must finish below $103.31 to avoid posting a weekly loss.