People visit a polling station to take part in the referendum on the status of Donetsk and Luhansk regions, in Moscow, on May 11
The self-proclaimed head of the "People's Republic of Donetsk" in eastern Ukraine on Monday 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.
Pushilin was speaking after he claimed 89 percent 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 Monday 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."