BEIRUT (Reuters) - The Syrian Kurdish PYD party rejects a Russian proposal to create de-escalation zones in Syria and views it as “sectarian partition” of the country, a spokesman said on Friday.

Iran and Turkey agreed on Thursday to the Russian plan, but the memorandum was not immediately published, leaving its details unclear.

The zones appear intended to halt conflict in specific areas between Syrian government forces and rebels, and would potentially be policed by foreign troops.

The plan amounts to “dividing Syria up on a sectarian basis,” said Ibrahim Ibrahim, a PYD spokesman, who described it as a “crime”.

The Syrian government, with the help of Russia and Iran, has gained the military upper hand against rebel groups, including some supported by Turkey, the U.S. and Gulf monarchies.

The Syrian government supported the de-escalation plan, but said it would continue to fight what it termed terrorist groups. Rebels rejected the deal and said they would not recognize Iran as a guarantor of any ceasefire plan.

Ibrahim said the Russian proposal could also threaten autonomous regions in the Kurdish-dominated north that emerged with the onset of the multi-sided conflict in 2011.

The PYD is the political affiliate of the YPG militia, which effectively serves as the military of the Kurdish-led enclaves and has appeared to be a key partner for the United States in fighting Islamic State in Syria.

The dominant Syrian Kurdish groups and their allies aim to deepen their autonomy through establishing a new system of federal government in the north. They say the regional federal model should be the solution to the entire Syrian war.

The countries involved in the de-escalation deal could thwart these plans and encroach on the autonomous regions, Ibrahim said.