Further price support came from renewed tensions over the contested nuclear program of oil producer Iran and more kidnappings in Nigeria, Africa's biggest exporter of crude.

New York's main oil futures contract, light sweet crude for delivery in July, gained 1.02 dollars to close at 65.20 dollars a barrel.

The US markets will be closed Monday for the Labor Day holiday.

In London, Brent North Sea crude for July delivery ended the day flat, a scant three cents lower at 70.69 dollars per barrel.

Traders covered their positions before the long US holiday weekend that kicks off the summer driving season that ends in September.

Continuing US refinery problems are curbing the supply of gasoline just as demand is set to soar.

"Concerns for tightening gasoline supplies have prevailed, of late and will continue to dominate until; prices begin to ease at the pump," said Mike Fitzpatrick of Man Financial.

The US Department of Energy said in its latest weekly snapshot that stockpiles of gasoline rose 1.5 million barrels in the week ending May 18 -- but they remained "well below the lower end of the average range."

Elsewhere, the United States led three allies Friday in warning the UN atomic chief against making comments that could harm the international drive against Iran's contested nuclear programme, diplomats said.

The US, British, Japanese and French ambassadors to the watchdog International Atomic Energy Agency met with IAEA director general Mohamed ElBaradei at his headquarters in Vienna.

They were protesting ElBaradei's statements in recent newspaper interviews that Iran should be allowed to enrich some uranium, the process which makes civilian reactor fuel but can also produce atom bomb material.

Western nations are concerned that Iran's nuclear programme is a front for an atomic weapons drive. Iran denies this, and analysts worry the dispute could lead to the Islamic republic cutting its oil exports.

Adding to global geopolitical jitters was news from fellow crude producer Nigeria.

Gunmen have kidnapped several oil workers in southern Nigeria, at least eight of them expatriates, police and diplomatic sources said.

One diplomat, who asked not to be identified, said the foreigners included four Britons, three US nationals, one South African and "possibly a Filipino."

The US State Department later confirmed three US citizens were kidnapped.

The kidnappings are the latest in a series of abductions to hit the restive Niger Delta since militants stepped up their attacks on oil firms and related sectors.