The number of people killed in eastern Ukraine since last April has now topped 6,000, despite successive ceasefires, a UN spokesman said Monday.
Ousted Ukrainian Viktor Yanukovych has requested Russian President Vladimir Putin in a letter to use force to help restore law and order in his turmoil-stricken country.
US Vice-President Joseph Biden, in phone talks with Russian Prime Minister Dmitry Medvedev Monday morning, urged Russia to support an immediate deployment of international monitors to Ukraine.
A Chinese envoy here on Monday called on all parties involved in the tense situation in Ukraine to seek a political solution to their disputes through dialogue and negotiations.
The United States suspended all military engagements with Russia because of Ukraine crisis, including military exercises and port visits.
Russian Foreign Affairs Minister Sergei Lavrov will meet the European Union's High Representative of Foreign Affairs Catherine Ashton on Tuesday to discuss the ongoing situation in Ukraine.
The United States has put trade and investment talks with Russia on hold as a rebuke for Russia's incursion into Ukraine, a US official said on Monday.
North Atlantic Treaty Organization announced to hold emergency talks on Ukraine in a statement.
The situation in Ukraine is affecting the economy in Poland, Polish central bank governor said.
Russian Foreign Minister Sergey Lavrov justified on Monday the use of Russian troops in Ukraine's Crimea region as a necessary protection for his country's citizens living there.
UN Secretary-General Ban Ki-moon called on Russia on Monday to avoid actions that might worsen the situation in crisis-hit Ukraine.
China's stance on the current situation in Ukraine is objective, just, fair and peaceful, Foreign Ministry spokesman Qin Gang said on Monday.