Top US officials back $1 billion lethal aid to Ukraine  The top Republican and Democrat on the House Armed Services Committee on Tuesday called for $1 billion in lethal defensive aid to Ukraine as Congress increased pressure on President Barack Obama to help Ukraine defend itself against Russian-backed rebels.  Rep. Mac Thornberry, R-Texas, the panel’s chairman, and Rep. Adam Smith of Washington state introduced legislation that would provide training, equipment and lethal defensive weapons to the national security forces of Ukraine through Sept. 30, 2017 to help secure “its sovereign territory against foreign aggressors.”  “It seems Russia has decided to go back to the Cold War,” Smith told reporters at a news conference, citing Russia’s takeover of Crimea and push into eastern Ukraine. The imposition of economic sanctions “has not at all changed President (Vladimir) Putin’s calculus.” Thornberry, who joined senators at a defense conference in Munich this past weekend, said “there’s a huge amount of bipartisan support to allow the Ukrainians to defend themselves.” Obama is considering sending lethal aid to Ukraine’s military. The president spoke Tuesday with the leaders of both Russia and Ukraine, one day before they meet for talks aimed at reaching an elusive peace deal. The White House said Obama reiterated US support for Ukraine’s sovereignty in his call with Russian President Vladimir Putin, and emphasized the importance of reaching a diplomatic resolution. “However, if Russia continues its aggressive actions in Ukraine, including by sending troops, weapons, and financing to support the separatists, the costs for Russia will rise,” the White House said in a statement.  Obama also discussed Wednesday’s cease-fire talks in Minsk, Belarus, with Ukrainian President Petro Poroshenko. The peace talks involve the leaders of France, Germany, Russia and Ukraine and come after nearly a year of fighting that the UN says has killed more than 5,300 people. More