 Image copyright Reuters Image caption Tensions between Russia and Nato countries are high over the ongoing conflict in Ukraine 
 
 Russia is to alter its military strategy as a result of the Ukraine crisis and Nato's presence in eastern Europe, a top Russian official says. In the latest in a string of setbacks in the past week, Ukraine's military said it had pulled back from defending a vital airport in the east of the country, near the city of Luhansk, where troops had been battling a Russian tank battalion. NATO appears to have shelved a proposal to permanently station alliance troops in new bases along its eastern flank, a measure sought by members such as Poland as a means of providing a deterrent to further Russian aggression. Several EU countries heavily dependent on Russian gas supplies, including the Czech Republic, Slovakia and Austria, opposed new measures, which require unanimous agreement. Russian Foreign Minister Sergei Lavrov on Tuesday said such efforts were "undermining" attempts to reach a peace deal with the rebels. On Monday, Ukraine's army said it had been forced to withdraw from Luhansk airport after it was attacked by Russian tanks. "A political solution is the only way out.  KIEV/MOSCOW Ukrainian President Petro Poroshenko accused Russia on Monday of "direct and undisguised aggression" which he said had radically changed the battlefield balance as Kiev's forces suffered a further reverse in their war with pro-Moscow separatists. Poroshenko said in a speech there would be high-level personnel changes in the Ukrainian armed forces, whose troops fled a new rebel advance in the south which Kiev and its Western allies say has been backed up by Russian armored columns. Russian President Vladimir Putin, who called on Sunday for immediate negotiations on the "statehood" of southern and eastern Ukraine, blamed Kiev's leadership for refusing to enter into direct political talks with the separatists.
– Tough talk as NATO-Russia relations continue to deteriorate: NATO leaders, who meet in the UK later this week, are planning a "rapid reaction" force that can deploy to Russia's worried Eastern European neighbors within 48 hours, reports the New York Times. The "spearhead" force would have a permanent command center to allow it to respond swiftly to threats, the Globe and Mail notes. "This spearhead ... could include several thousand troops, ready to respond where needed with air, sea, and special-forces support," NATO Secretary-General Anders Fogh Rasmussen told reporters. The NATO summit in Newport, Wales, is especially important because "Russia thought it can change the borders of a sovereign European country by force, and this is happening not very far from NATO's borders," says Estonian Prime Minister Taavi Roivas, calling for fresh plans to ensure all members of the alliance are "equally and strongly protected." Russian defense chiefs, meanwhile, say NATO's actions are "evidence of the desire of US and NATO leaders to continue their policy of aggravating tensions with Russia" and that Moscow plans to craft a new military doctrine in response to NATO plans and the Ukraine crisis, the BBC reports. In Ukraine, President Petro Poroshenko accused Russia of "direct and undisguised aggression" yesterday as government forces continued to suffer reverses, including a retreat from the Luhansk airport, where the Ukrainian military says a Russian tank battalion supported pro-Russia rebels, Reuters reports.