KABUL: The US ambassador to Afghanistan, Ryan Crocker, is to leave his post this summer, the embassy in Kabul confirmed Tuesday.

“Amb Crocker has confirmed with regret that he will be leaving Kabul this summer,” the embassy said on its Twitter feed, a day after the conclusion of a Nato summit in Chicago in which leaders charted a path out of the Afghan war.

The veteran diplomat, who was appointed to Kabul 10 months ago, previously served as the US envoy to Iraq, Pakistan and Syria.

No reason was given for Crocker's departure and an embassy official told AFP: “We have nothing further on that at this time.”

CBS news, which earlier reported on Crocker's plans, quoted a senior State Department official as saying only that Kabul is “a tough place to serve.”

Crocker was appointed out of retirement in July 2011.

He had previously served as ambassador to Iraq from 2007-2009, during a period in which violence dropped dramatically and the two countries signed a military pact providing for the eventual withdrawal of all US forces.

In recognition of his efforts, Crocker received the Presidential Medal of Freedom, the country's highest civilian honour, in 2009.

He was ambassador to Pakistan from 2004-2007 and to Syria from 1998-2001.