US President Donald Trump has vetoed a $740bn defence spending bill that passed Congress this month.

Trump has objected to provisions that limit troop withdrawals from Afghanistan and Europe and remove Confederate leaders' names from military bases.

He also wanted it to repeal a liability shield for social media companies.

Lawmakers passed the measure with an overwhelming majority and could override the president's rejection.

Bills passed by Congress need a president's signature to become law. On rare occasions, a president may choose to veto - or reject - legislation because of some policy disagreement.

President Donald Trump on Wednesday vetoed the sweeping defense bill that both chambers of Congress recently passed by veto-proof majorities, setting up a possible veto override vote that could pit members of his own party against him.

Trump had previously threatened to veto the defense bill, known as the National Defense Authorization Act, because it doesn't include a repeal of Section 230, a law that shields internet companies from liability for what is posted on their websites by them or third parties.

"Unfortunately," the President wrote in his veto message to Congress, "the Act fails to include critical national security measures, includes provisions that fail to respect our veterans and our military's history, and contradicts efforts by my Administration to put America first in our national security and foreign policy actions. It is a 'gift' to China and Russia."