MOSCOW, March 10 - Russia vowed on Monday to unveil its own solution to the Ukrainian crisis that would run counter to US efforts and would appear to leave room for Crimea to switch over to Kremlin rule, AFP reported.

The unexpected announcement came as Ukraine's new pro-European leaders raced to rally Western support in the face of the seizure by Kremlin-backed forces of the strategic Black Sea peninsula and plans to hold a Sunday referendum on switching Crimea's allegiance from Kiev to Moscow.

Russian President Vladimir Putin's threat to invade Ukraine after a wave of deadly protests toppled a pro-Kremlin regime last month has set off the most explosive crisis in East-West relations since the Cold War.

US President Barack Obama and his European allies are urging Russia to call its troops in Crimea back to their barracks and launch immediate negotiations with the new Ukrainian leadership, which Putin claims rose to power thanks to an "unconstitutional coup.”

Russian Foreign Minister Sergei Lavrov told Putin in a televised meeting Monday that proposals he had received from US Secretary of State John Kerry on resolving the standoff "do not suit us very much" and were "framed as if there exists a conflict between Russia and Ukraine."

He said Russia had prepared a series of counter-proposals that would "take into account the interests of all Ukrainians".

Lavrov said Washington was basing its solution on a recognition of Kiev's new leaders while Russia still considered the ousted Viktor Yanukovych as the legitimate president of Ukraine.

But Lavrov gave no indication about when or where Russia's proposals would be made public.

Ukraine's interim Defense Minister Igor Tenyukh meanwhile said the nation's army -- already on full combat alert -- had launched training exercises aimed at evaluating how the heavily outnumbered force could resist an offensive from its nuclear-armed neighbor.

The diplomatic wrangling continued as Prime Minister Arseniy Yatseniuk prepared to fly to the United States to meet Obama and address the UN Security Council.

His first meeting with the US leader on Wednesday should add credibility to Yatseniuk untested government and provide Ukraine with a chance to iron out the details of crucial economic relief for its struggling economy.

The White House said Obama will discuss an economic support package that has already seen Washington pledge a quick infusion of more than $1 billion and the European Union promise to issue 11 billion euros ($15 billion) over two years.

Kiev says it needs about 25 billion euros ($35 billion) through 2015 to keep the country running after Russia froze a $15-billion bailout it promised Yanukovych as his reward for rejecting an EU trade deal in November that initially sparked the protests. (afp/ez)