Manila - Secretary of State Rex Tillerson said on Monday he had told his Russian counterpart that Moscow's meddling in the US presidential election had created "serious mistrust" between the two countries.After meeting Foreign Minister Sergei Lavrov in Manila, Tillerson said he had also warned him Washington was deciding on a response to the Kremlin's decision to order a cut in the size of the US mission in Moscow."Russian meddling in the elections was certainly a serious incident. We talked about that in the discussion that we had with Mr Lavrov yesterday," Tillerson told reporters."And trying to help him understand just how serious this incident had been and how seriously it had damaged the relationship between the US and the American people and the Russian people, that this had created serious mistrust and that we simply have to find some way to deal with that."Russia has furiously denied reports endorsed by US intelligence agencies that it attempted to swing last year's US presidential in favour of the eventual victor, President Donald Trump.Trump has played down the allegations, but the ongoing controversy cast a pall over already tense ties, which most recently saw President Vladimir Putin order the US diplomatic mission in Moscow cut 755 personnel."I told the foreign minister that we have not made a decision about how we would respond to the Russian request to remove US diplomatic personnel," Tillerson said."I asked several clarifying questions, just to describe the thinking behind that diplomatic note that we received, but I told them we would respond by September 1," he said, referring to Moscow's deadline to shrink the mission.