The US government's unprecedented use of National Guard troops in Los Angeles to protect officers carrying out President Donald Trump's immigration crackdown was illegal and should be ended, a lawyer for the state of California told a federal judge.

The trial for California Gov. Gavin Newsom's lawsuit against President Trump's National Guard deployment in Los Angeles began Monday. CBS News' Katrina Kaufman has more details.

A federal trial is underway to determine the legality of President Donald Trump's federalization of the National Guard in Los Angeles to quell protests against local Immigration and Customs Enforcement operations in June.