Vienna (Reuters) The UN nuclear agency chief said yesterday he had formally urged Syria to provide his inspectors with speedy access to the remains of a suspected atom site, signalling growing frustration over the issue.

For more than two years Syria has blocked International Atomic Energy Agency (IAEA) access to the remains of a desert site which US intelligence reports say was a nascent North Korean-designed nuclear reactor intended to produce bomb fuel.

The site, known as either Al Kibar or Dair Al Zour, was bombed to rubble by Israel in 2007. Syria, an ally of Iran, denies ever having an atom bomb programme.

In a report last month Yukiya Amano, the IAEA director general, said Syria was not allowing UN nuclear inspectors to visit numerous suspect sites and had provided scant or inconsistent information about its atomic activities.

on Thursday, he told the IAEA's 35-nation governing board he had written a letter to Syrian Foreign Minister Walid Mua'allem on November 18, a move a diplomat close to the probe said reflected "the growing urgency" of the matter.

"I wrote a letter ... to request the government to provide the agency with prompt access to relevant information and locations related to Dair Al Zour," Amano told the closed door meeting, according to a copy of his speech.

"I also requested Syria's cooperation regarding the agency's verification activities in general," he said.

Earlier this year the IAEA gave some weight to suspicions of illicit nuclear work at the site by saying that uranium traces found during a 2008 visit by inspectors pointed to nuclear-related activity.