MOSCOW, March 16 (Reuters) - Russian President Vladimir Putin reiterated on Sunday that the secession referendum in Ukraine's Crimea complied with international laws and promised to respect the region's decision on whether to join Russia.
Western countries have called the vote by the mostly Russian-speaking region illegal and have warned of sanctions against Moscow, saying the referendum is being conducted at the barrel of a gun as Russia built up its troops in Crimea.
In a phone call with German Chancellor Angela Merkel, Putin said the referendum complied with international law, including Article 1 of the U.N. Charter which states the principle of self-determination of peoples.
"It was emphasized that Russia will respect the choice of Crimean people," a Kremlin statement said.
In the Crimean peninsula the polling stations are to close at 1800 GMT. Provisional results will be released late on Sunday with the final tally expected a day or two later.
Putin and Merkel also discussed the possibility of sending Organisation for Security and Cooperation in Europe (OSCE) observers to Ukraine to monitor the situation, the Kremlin said.
According to Merkel's spokesman, Putin welcomed the German chancellor's proposal to swiftly expand the existing OSCE presence in Ukraine, especially in East Ukraine.
The Kremlin's statement only said there was a "constructive exchange of views on the possible deployment in Ukraine of a large-scale OSCE mission to monitor the situation."
As Crimean were casting their votes, Ukrainian Prime Minister Arseny Yatseniuk vowed to track down and bring to justice all those promoting separatism in its Russian-controlled region of Crimea "under the cover of Russian troops". [ID:nL6N0MD0H1 ]
After Moscow-backed Ukrainian President Viktor Yanukovich was overthrown in Kiev, deadly violence erupted in the country's east, with dozens of people hurt in clashes in the city of Donetsk.
Putin expressed his concerns about an escalation of tensions in the southeastern regions that he said were caused by radical groups in "connivance with Kiev's authorities".
Russian Foreign Minister Sergei Lavrov urged his U.S. counterpart John Kerry on Sunday to use the influence of the United States to encourage authorities in Kiev to stop what he called "massive lawlessness" against the Russian-speaking population.
In their second phone conversation in two days, Lavrov and Kerry agreed to seek a solution to crisis in Ukraine by pushing for constitutional reforms there, Russia's foreign ministry said in a statement.
It did not go into details on the kind of reforms needed except to say they should take into account the interests of all regions of Ukraine.