Western powers seeking to de-escalate the crisis in Ukraine face a major diplomatic challenge after Russia's intervention in Crimea placed them on the back foot. Here are some of the key issues: - Are Western powers on the same page about Russia's intervention? Yes, inasmuch as they have firmly criticised Moscow's move, describing it as an "aggression" that "violates international law". There is also wide agreement that a military solution should be ruled out. "As things stand, no one is prepared to die for Sevastopol," one European diplomat said. Western countries are all calling for a "de-escalation", but they differ on the best way to apply pressure on Russian President Vladimir Putin. The United States has adopted a firmer tone than the Europeans, suspending military cooperation and brandishing a "wide range" of economic and diplomatic sanctions with the purpose of isolating Russia. The European Union is also suggesting sanctions, albeit on a smaller scale, but first it wants to give dialogue with Moscow a chance, while displaying strong support for the new Ukrainian administration. Ukraine's Prime Minister Arseniy Yatsenyuk will be received in Brussels ahead of an emergency summit of EU leaders on Thursday. - Russian neighbours advocate a tougher line while Germany favours dialogue Within the European Union, Poland and the Baltic states (former Soviet republics Estonia, Latvia and Lithuania) which border on Russia are calling for "intransigence" in dealing with Moscow because they believe that the Ukrainian crisis destabilises the entire region. "What is at stake is the entire Eurasian and European continent that was established after the Cold War," said Temuri Yakobashvili, a former Georgian ambassador to the United States. Lithuania's President Dalia Grybauskaite believes that Crimea has become a "new frozen conflict", similar to the situation after the 2008 separatist war between Georgia and Russia over South Ossetia and Abkhazia, which "may have serious consequences for the security of the whole region". Russia fought a brief war with Georgia in August 2008 and then backed the independence of the two breakaway regions, stationing troops there. For its part, Germany is attempting to play the role of mediator, banking on its strong diplomatic ties with Russia. Chancellor Angela Merkel, who speaks Russian, and Putin spoke to each other twice over the weekend. German Foreign Minister Frank-Walter Steinmeier said that diplomacy was "not a weakness" but acknowledged there was no solution in sight after a "long and difficult" conversation with his Russian counterpart, Sergei Lavrov. Germany is also keen to protect its economic interests in Russia -- a concern shared by Britain and France. - Has the West already written off Crimea? Not officially. All players are standing up for the "territorial integrity and unity of Ukraine". However, according to Andy Kuchins, Russia/Eurasia program director with think-tank CSIS, "if we are not willing to risk a military conflict then we would have to ... accept" the reality of Moscow's territorial claim over the majority Russian-speaking region which is home to Russia's Black Sea Fleet. - Does the West have the means to protect other former Soviet republics which want to move closer to the European Union, such as Georgia ad Moldova? According to one senior EU official, this is one of Brussels' priorities because "the EU can't afford to lose Georgia and Moldova", the only two former Soviet republics that still wish to sign up to an association agreement with the EU, following the decision of Ukraine and Armenia to back away. "We need to fast-track the process for them to sign up," the official said. The United States has also been sending out signals of support to Moldova, which is locked in a dispute with Russia over Transdniestr, a majority Russian-speaking region that announced its secession from Moldova in 1990 and where Moscow has stationed troops. In a meeting with Moldovan Prime Minister Iurie Leanca, US Secretary of State John Kerry said Moscow "has put pressure on Moldova".