The self-proclaimed head of the "People's Republic of Donetsk" in eastern Ukraine yesterday declared the region a sovereign state and asked Russia to consider allowing it to accede.
"Proceeding from the expression of the will of the people of the Donetsk People's Republic and in order to restore historical justice, we ask the Russian Federation to consider the issue of the Donetsk People's Republic becoming part of the Russian Federation," Denis Pushilin told reporters.
Watch: Eastern Ukraine rebels see Russian future after referendum
Pushilin was speaking after he claimed 89 per cent of people in the region supported independence in Sunday's referendum, slammed as illegal and a farce by both the West and Kiev.
"We, the people of the Donetsk People's Republic, based on the results of the referendum held on 11 May 2014 ... declare that the [republic] is henceforth a sovereign state," Pushilin said.
Pushilin had said earlier that a presidential election that the West sees as vital to ease tensions in the crisis-wracked country "will not happen" in the Donetsk region.
This raised the possibility of stronger Western sanctions against Russia, whom the West blames for fomenting unrest in the former Soviet republic.
US President Barack Obama has said he will impose sanctions that target whole sections of the recession-threatened Russian economy if the elections do not go ahead as planned.
The European Union on yesterday ramped up sanctions over the Ukraine crisis, adding two Crimean firms and 13 people to an existing blacklist.
Reacting to the referendums in the regions of Donetsk and Lugansk, Russian President Vladimir Putin's office said that "Moscow respects the expression of the people's will" there.
Putin called for the results to be "implemented in a civilised manner, without any repeat of violence, through dialogue between representatives of Kiev, Donetsk and Lugansk".
Germany meanwhile announced plans for Foreign Minister Frank-Walter Steinmeier to travel today to Kiev and eastern Ukraine to support efforts to mediate a "national dialogue" between Kiev and pro-Moscow groups.
Denounced by the Kiev government and the West as "a farce", the contentious vote was hastily organised and held with no international observers.
It deepened a crisis that has brought Russia's relations with the West to their lowest point since the cold war.
The United States and other Western countries have said they will not recognise the outcome of the vote, which comes some two months after Moscow annexed Ukraine's Crimea peninsula.
"The farce that terrorist separatists call a referendum is nothing more than propaganda to cover up murders, kidnappings, violence and other serious crimes," Ukraine's interim President Oleksandr Turchynov told parliament. But he repeated his desire to "continue dialogue with those in the east of Ukraine who have no blood on their hands and who are ready to defend their goals in a legitimate way."
Separatist officials in Donetsk said 89 per cent of voters backed breaking away from Ukraine in Sunday's referendum, with a turnout of 75 per cent. Rebel officials in Lugansk said 94 per cent had backed independence.
The rebels prevented foreign media from observing ballot counting and voting took place with no neutral monitors, incomplete electoral rolls, and a haphazard registration procedure that did nothing to prevent multiple voting.
The two industrial regions are home to seven million people, out of Ukraine's total population of 46 million.
Pushilin also said Ukraine's May 25 presidential election, seen as vital to restoring order, "will not happen" in Donetsk.
The crisis has raised fears of a violent break-up of Ukraine and the possibility of a civil war on Europe's eastern edge.
Kiev and Western leaders have accused Moscow of backing the rebels and yesterday EU foreign ministers announced the latest sanctions against Russians and Crimeans involved in the crisis.