Brent crude futures slipped towards $120 on Monday after weak growth numbers from China, the world's No. 2 oil consumer, and a surge in Spanish borrowing costs triggered worries about global economic growth and demand.
China's economy grew 8.1 percent in the first quarter from 8.9 percent in the previous quarter, weaker than expected and the slowest growth in nearly three years, raising fears that the downward drift will extend into the second quarter and dampen oil demand.
A stronger dollar and a jump in the cost of insuring Spanish debt against default to a record high on Friday renewed worries about the eurozone debt crisis, pressuring oil prices further.
Front-month Brent crude slipped 1.17 to $120.04 a barrel by 0311 GMT, after settling at $121.21 a barrel on Friday. U.S. oil slipped 64 cents to $102.20 a barrel after settling at $102.83.
"The weaker than expected Chinese data appears to be the key driver of the market right now," said Tetsu Emori, a Tokyo-based commodities fund manager at Astmax Investments.
China's implied oil demand rose moderately in March over a year earlier, but stood at a five-month low on a daily basis, as refineries scaled back runs to the lowest level since October on maintenance and poor refining margins.
Investors were also worried after a survey in the U.S. showed consumer sentiment had slipped in early April as higher gasoline prices hit household budgets.
The dollar index rose 0.26 percent on Monday. A stronger dollar makes the commodity more expensive for consumers using other currencies.
Oil prices were also under pressure after top oil exporter Saudi Arabia's Oil Minister Ali al-Naimisaid on Friday that the country is determined to bring down high oil prices and is working with fellow OPEC members to accomplish that.
Naimi reiterated that there were no supply shortages in the global oil market and the kingdom stood ready to use its spare production capacity if necessary.
Concerns that further western sanctions could disrupt more Iranian oil exports offset worries on the global economy.
"The market is looking at the Middle East as well, especially on Iran's nuclear weapons program, as the issue needs to be resolved as soon as possible ahead of the U.S. elections," said Emori.
U.S. President Barack Obama said there would be more sanctions imposed on Iran if there is no breakthrough in nuclear talks with global powers in the coming months, responding to Israeli accusations that Tehran has been given a "freebie."
At a news conference in Cartagena, Colombia, where he was attending the Summit of theAmericas, Obama said negotiations between Iran and six world powers that resumed on Saturday would not stretch on indefinitely and would require Iran to act.
The potential for supply disruption and tightening sanctions have helped push crude prices higher in 2012. The European Union's ban on importing Iranian oil set to start in July has already curbedTehran's exports.