Some of the most senior United States (US) diplomats focused on Syria have been abruptly let go from their posts in recent days, according to five people familiar with the matter, a shake-up that comes as Washington seeks to integrate its Syrian Kurdish allies with the central administration in Damascus.

The diplomats at the Syria Regional Platform (SRP), the de facto US mission to the country based remotely in Istanbul, all reported to Tom Barrack, the US special envoy for Syria and a longtime adviser and friend of President Donald Trump.

Appointed in May, Barrack has spearheaded a regional policy shift that backs a unified Syrian state under President Ahmed al-Sharaa, who swept to power in a lightning advance late last year.

One of the people who spoke to Reuters, a US diplomatic source, said “a handful” of staff at the SRP were told their tours were ending as part of a reorganisation of the team.

The person said the departures would not affect US policy in Syria, and the decision to remove them was not based on policy differences between the staff and Barrack or the White House.

The sources, who also included two Western diplomats and two US-based sources, said the moves were sudden, involuntary and came toward the end of last week. Reuters was not able to ascertain the official reason given for the moves.

A State Department official said it did not comment on “personnel decisions or administrative reorganizations”, adding:” Core staff working on issues pertaining to Syria continue to operate from multiple locations.”

Barrack, the envoy, has urged the Kurdish-led, US-backed Syrian Democratic Forces (SDF) to move more quickly to ratify a March deal with al-Sharaa to bring areas they run under state authority, and to integrate the SDF into national security forces.