Pro-Moscow separatists in eastern Ukraine ignored a public call by Russian President Vladimir Putin to postpone a referendum on self-rule, declaring they would go ahead on Sunday with a vote that could lead to war.

The decision, which contradicted the conciliatory tone set by Putin just a day earlier, caused consternation in the West, which fears the referendum will tear Ukraine apart.

US Deputy Secretary of State William Burns said Russia was heading down a “dangerous and irresponsible path” and the situation in Ukraine was “extremely combustible”. Denis Pushilin, a leader of the self-declared separatist Donetsk People’s Republic, expressed gratitude to Putin but said the “People’s Council” had voted unanimously yesterday to hold the plebiscite as planned.

“Civil war has already begun,” he told reporters. “The referendum can put a stop to it and start a political process.” A man holding a Kalashnikov stood behind him.

Political analysts said Putin may have expected the rebels to go ahead with the referendum, showing that they were not under his orders. By distancing himself from a process that will not be recognised by the West, Putin may also hope to avoid further sanctions as earlier measures begin hitting the economy.

Separatists declare they will go ahead on Sunday with vote that can lead to war

His spokesman said the Kremlin needed more information about the rebels’ decision. He also said the rebel statement came only after the Western-backed government in Kiev had declared it would press on with its military operation, implying that Ukraine was to blame for the rebels’ refusal to heed Putin.

Russian markets sank after surging on Wednesday when Putin unexpectedly called for the vote to be delayed and declared that troops were withdrawing from Ukraine’s border.

Nato and the US both said they saw no sign of a Russian withdrawal from the frontier.

When Nato Secretary General Anders Fogh Rasmussen tweeted as much, the Russian Foreign Ministry tweeted back that “those with a blind eye” should read Putin’s statement.

Nato has accused Moscow of using special forces in the separatist takeover of mainly Russian-speaking eastern Ukraine after annexing Crimea from Ukraine in March.

Putin acknowledged his troops were active in Crimea after initially denying any role there but says they are not involved in eastern Ukraine.