The United States and its European allies must not build any bases in the former Soviet Union or use those countries for military purposes, warned Russian Foreign Minister Sergei Lavrov on Tuesday. Lavrov, quoted by Russian state-run news agencies RIA and TASS, said the Kremlin found it unacceptable that some European nations are hosting U.S. nuclear weapons and again said Russia is taking measures to stop Ukraine from obtaining similar weapons. He did not provide evidence for the claim. “It is high time to bring American nuclear weapons home, and to completely eliminate the infrastructure associated with them in Europe,” he said at a U.N. video conference on Tuesday. As Lavrov started to speak, video footage showed more than 100 U.N. diplomats leaving their seats and walking out of the room. Earlier this week, the governments of the Czech Republic and Slovakia—formerly Soviet satellite states—said they would increase military aid …