KABUL, May 22: The US ambassador to Afghanistan, Ryan Crocker, would leave his post early, the embassy confirmed on Tuesday, a day after Nato leaders charted a path out of the Afghan war at a summit in Chicago.

The veteran diplomat, who was appointed to Kabul 10 months ago for a two-year term, previously served as the US envoy to Iraq, Pakistan and Syria.

“Ambassador Crocker has confirmed with regret that he will be leaving Kabul this summer,” the embassy said on its Twitter feed.

No reason was given for Mr Crocker’s early departure and an embassy official said: “We have nothing further on that at this time.”

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

Now aged 62, Mr Crocker was appointed out of retirement in July 2011. His early departure coincides with that of US ambassador to Pakistan, Cameron Munter, and reports that US General John Allen is about to become the fourth Nato commander in Afghanistan to leave early, tipped for a job in Europe.

The United States has nearly 100,000 troops in Afghanistan — out of a Nato total of 130,000 — fighting an armed campaign by the Taliban against the government of President Hamid Karzai.

During his term, Mr Crocker oversaw thorny negotiations leading to the signing of a Strategic Partnership Agreement with Afghanistan, designed to govern relations between the two countries after Nato troops pull out in 2014.

But ties have been rocked by a series of incidents in recent months, including a video showing US troops urinating on Taliban corpses, riots provoked by the burning of the holy Quran at a US military base and a massacre of 17 civilians blamed on an American soldier.

Details of the number of US troops who may remain in the country after 2014, and their status, are yet to be worked out in a separate security pact.

Mr Crocker, along with Gen Allen, was summoned to Mr Karzai’s palace earlier this month after a number of civilians were killed in Isaf air strikes. President Karzai said then that the civilian deaths threatened the strategic pact.

But both Mr Crocker and Mr Karzai were in Chicago for the Nato summit, where US President Barack Obama and his allies ratified an “irreversible” roadmap to “gradually and responsibly” withdraw their combat troops by the end of 2014.

Mr Crocker 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, Mr 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.—AFP