Washington, March 15 (RHC-Commondreams)-- Unsuccessful talks between Russia and the U.S., increased Russian troop presence, and a pending referendum vote bring continued uncertainties and tensions as the crisis in Ukraine continues to unfold.

U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov held a nearly six-hour meeting in London, which was said to come to no diplomatic resolution.

Lavrov said the talks were "useful" yet brought about "no common vision" between the two countries.

Kerry told reporters that "there will be consequences if Russia does not find a way to change course."

The Guardian reported that the meeting's failure brought the crisis to "a new and more dangerous phase" and "sets Russia on a collision course with the west."

Kerry said that “the foreign minister made it clear that President Putin is not prepared to make any decision regarding Ukraine until after the referendum on Sunday.”

In that referendum, residents of the Crimean Peninsula will vote whether to separate from Ukraine and join Russia or to choose effective independence.

Kerry said, "Neither we nor the international community will recognize the results of this referendum."

"We believe the referendum is contrary to the constitution of Ukraine, contrary to international law, is in violation of that law, and is illegitimate." he said. Lavrov, meanwhile, told reporters, "We will respect the will of people of Crimea that will be expressed at the referendum on the 16th of March."

Kerry has warned that if the vote takes place, Russia faces EU and U.S. sanctions.

"I assure you that our partners understand that sanctions are counterproductive ... and (they) will not facilitate mutual interests," Lavrov said.

In related news, Moscow has expressed disappointed with the statement of the Organization for Security and Cooperation in Europe (OSCE) over the upcoming referendum in Crimea, the Russian Foreign Ministry said Friday.

"In its current form the referendum regarding Crimea scheduled for March 16, 2014, is in contradiction with the Ukrainian Constitution and must be considered illegal," the website of the Organization for Security and Cooperation in Europe quoted Didier Burkhalter as saying.

Moscow insisted that it considers the Sunday referendum completely legal, citing the Helsinki Act of 1975 which guarantees a right for all nations to decide freely their internal and external political status.

It also expressed regret that the Swiss chairmanship of the OSCE had put a blind eye on "anti-constitutional coup" in Ukraine and on legitimacy of the new regime in Kiev.

"We hope the chairmanship's possible assessments of these issues will take Russian point of view into account," the ministry said.

Moscow called on the bloc to drop double standards and accept invitation of Crimean authorities for monitoring mission during the referendum, which would facilitate de-escalation of tension in that region.

The crisis in the mostly Russian-speaking Crimea began in late February following the ouster of Ukrainian President Viktor Yanukovych.