Brent crude eased towards $110.50 a barrel on Monday but was supported near a five-month high as tensions over a suspected chemical weapons attack in Syria spurred concerns that increased unrest in the Middle East could disrupt supply.
Oil prices had gained alongside equities after a steep drop in new U.S. home sales tempered expectations the Federal Reserve would soon reduce stimulus.
A large drop in U.S. durable goods data added to the bearish sentiment that the recovering U.S. economy was not quite strong enough for an end to economic stimulus. More dollar printing, on the hand, also supports higher oil prices.
Brent crude for October fell 33 cents to $110.71 a barrel at 1315 GMT, after touching $111.68 in early trade, the highest since April 2.
U.S. crude for October delivery fell 24 cents to $106.18 a barrel.
Large speculators raised their net long positions in Brent futures and options to a new record high in the week to Aug. 20.
"We think that both WTI and Brent are likely to hit technical resistance at getting much past $106 and $110 a barrel. Today this will not be easy to overcome," Tobias Merath, head of private banking commodity research at Credit Suisse, said.
"The geopolitical premium is at $10 right now. Premia of more than $10 on Middle East unrest are rarely sustainable... and oil is unlikely to rise further, particularly with poor economic numbers from the U.S."
U.N. inspectors left central Damascus on Monday to investigate sites of an alleged chemical weapons strike on the outskirts of the Syrian capital, a Reuters witness said, after calls from Western powers for military action to punish what may be the world's worst chemical attack in 25 years.
"Bets are hedged for a new conflict in Syria," Thorbjoern Bak Jensen, analyst at Global Risk Management said. "If something happened, it could spread to other countries and disrupt oil supplies."
Orders for long-lasting U.S. manufactured goods recorded their biggest drop in nearly a year in July and a gauge of planned business spending on capital goods tumbled, casting a shadow over the economy early in the third quarter.
Tighter supply due to disrupted output from the North Sea to Libya has pushed Brent higher over the past two weeks, while positive economic data from the euro zone and China last week improved the outlook for fuel demand. (Additional reporting by Florence Tan in Singapore, Editing by Jason Neely)