British Prime Minister Keir Starmer said on Tuesday he would not be deterred from supporting Ukraine by "irresponsible" Russian rhetoric, after Russian President Vladimir Putin lowered the threshold for a nuclear strike. "There's irresponsible rhetoric coming from Russia, and that is not going to deter our support for Ukraine," he told reporters at the G20 summit in Brazil. Putin's new nuclear doctrine lowers the threshold under which Russia might use atomic weapons to include responding to attacks that threaten its territorial integrity. The move comes as Ukraine used U.S. ATACMS missiles to strike Russian territory on Tuesday, taking advantage of...