Anarchist groups have threatened to shut down Republican Donald Trump's swearing-in as U.S. president, but police in Washington said on Friday they believe the thousands of security officers assigned to the event will be able to head off any disruption. Dozens of activist groups plan to protest the Jan. 20 inauguration of the New York real estate developer, whose supporters are counting on him to fulfill a host of controversial campaign promises including building a wall on the Mexican border and deporting millions of illegal immigrants. Police expect some 900,000 people to flood Washington for the inauguration ceremony, which includes a parade from the U.S. Capitol to the White House along streets thronged with onlookers. Interim Police Chief Peter Newsham told reporters on Friday that in…