By Joseph Ax (Reuters) -Hundreds of additional National Guard troops are headed to Washington, D.C., from half a dozen Republican-led states, bolstering President Donald Trump's extraordinary move to flood the Democratic-led city with soldiers and federal agents in what he claims is an effort to fight violent crime.

A federal judge heard arguments this week on whether military troops deployed this summer by the Trump administration to Los Angeles violated a federal law that bars troops from conducting law enforcement duties within the country.