Under the plan, agreed by presidents Tayyip Erdogan and Vladimir Putin, Syrian Kurdish forces are to withdraw more than 30km from the Turkish border
The Kurdish-led Syrian Democratic Forces (SDF) accused Turkey on Thursday of launching a large land offensive targeting three villages in northeast Syria despite a truce, but Russia said a peace plan hammered out this week was going ahead smoothly.
Under the plan, agreed by presidents Tayyip Erdogan and Vladimir Putin, Syrian Kurdish forces are to withdraw more than 30km from the Turkish border, a goal Russia's RIA news agency, quoting an SDF official, said was already achieved.
Russia said it was sending more military policemen and heavy equipment to help implement the deal, which has already prompted US President Donald Trump to lift sanctions against Turkey and has drawn lavish praise for Erdogan in the Turkish media.
Ankara views the Kurdish YPG militia, the main component in the SDF, as terrorists linked to Kurdish insurgents in southeast Turkey. It launched a cross-border offensive against them on Oct. 9 after Trump ordered US forces out of northeast Syria.
The deal agreed with Putin, which builds on and widens a previous US-brokered ceasefire, helped end the fighting.
But the SDF said in its statement on Thursday that Turkish forces had attacked three villages "outside the area of the ceasefire process," forcing thousands of civilians to flee.
"Despite our forces' commitment to the ceasefire decision and the withdrawal of our forces from the entire ceasefire area, the Turkish state and the terrorist factions allied to it are still violating the ceasefire process," it said.
"Our forces are still clashing," it said, urging the United States to intervene to halt the renewed fighting.
There was no immediate comment from Turkey, which has previously said it reserves the right to self-defence against any militants who remain in the area despite the truce.