BY TOM PERRY AND ARSHAD MOHAMMED

A senior U.S. official visited northern Syria at the weekend to assess progress in the fight against Islamic State, in what appeared to be the first declared visit to Syrian territory for several years by an official from U.S. President Barack Obama's administration.

The Syrian Kurds have established control over wide areas of northern Syria since the eruption of the country's war in 2011, and their YPG militia has become a major partner in the U.S.-led coalition against Islamic State.

The trip by Brett McGurk, the U.S. envoy to the coalition against Islamic State, may anger neighboring Turkey which is alarmed by the growing sway of Syria's Kurds, fearing it could fuel separatist sentiment among its own Kurdish population.

"We can confirm that Special Presidential Envoy Brett McGurk completed a two day visit to northern Syria this weekend to assess progress in the campaign to degrade and destroy ISIL," the U.S. official said, using an acronym for Islamic State.

"This visit and the discussions he had are in keeping with the Special Envoy's efforts to continue looking for ways to increase coalition pressure on ISIL," the official said.

Fred Hof, a Syria expert with the Atlantic Council think tank, said to his knowledge this was the first declared visit to Syria by a U.S. government official since the February 2012 closure of the U.S. embassy in Damascus.

The Syrian Kurdish official told Reuters McGurk landed at a Kurdish-controlled airport being used by U.S. military helicopters for logistical purposes and deliveries.

McGurk was received by officials including the prime minister of one of three autonomous regions, or cantons, the Syrian Kurds have set up in northern Syria.

In a statement posted on Youtube, Akram Hasso, head of the administration of Jazeera province, said McGurk's delegation was 17 strong and included representatives of France and Britain.

He also said they visited Kobani, a Syrian Kurdish town at the Turkish border that was the focus of a months-long battle between the YPG and Islamic State.

(Writing by Tom Perry; Editing by Dominic Evans)

REUTERS