Russia pledged to scale down fighting around Kyiv and a second major city following peace talks on Tuesday that Ukraine's leader said showed "positive" signs, but Western allies made clear their doubts over Moscow's intentions. US President Joe Biden spoke with Johnson and the leaders of France, Germany and Italy, together vowing no let up in the strong economic sanctions imposed on Moscow. "We'll see if they follow through on what they're suggesting," Biden told reporters following the call, when asked if he believed Russia was simply trying to buy time.