SAN FRANCISCO - Twitter on Tuesday slapped a fact-check label on President Donald Trump's tweets for the first time, a response to long-standing criticism that the company is too hands-off when it comes to policing misinformation and falsehoods from world leaders.

The move, which escalates tensions between Washington and Silicon Valley in an election year, was made in response to two Trump tweets over the past 24 hours. The tweets falsely claimed that mail-in ballots are fraudulent. Twitter's label says, "Get the facts about mail-in ballots," and redirects users to news articles about Trump's unsubstantiated claim.

Twitter’s actions come on a day when Twitter was facing a barrage of criticism over another set of Trump tweets. Earlier on Tuesday the widower of a former congressional staffer for Joe Scarborough has asked Twitter chief executive officer Jack Dorsey to delete tweets by Trump furthering a baseless conspiracy theory about his wife’s death.