The Kremlin said a ceasefire announced by Ukrainian President Petro Poroshenko is an ultimatum to pro-Russian separatists rather than an offer of peace, Russia's Interfax news agency has reported.
"This is not an invitation to peace and negotiations, but an ultimatum to militias in the southeast of Ukraine to lay down their arms," the Kremlin was quoted as saying.
It also claimed that a Russian checkpoint on the Ukrainian border had come under fire and demanded "an explanation and an apology" from Kiev.
More top news
Russia has announced that it will expel 23 UK diplomats in a deepening rift over the poisoning of a Russian ex-spy and his daughter.
A letter signed by both Carwyn Jones and Nicola Sturgeon spells out the key points in their stand off with the UK Government over Brexit.
The National People's Congress also appointed close Xi ally Wang Qishan to the formerly ceremonial post of vice president.