Washington, Jun 7 (IANS): The White House has defended tweets by US President Donald Trump that have raised concern among opponents and allies alike.

"I think his use of social media ... gives him an opportunity to speak straight to the American people, which has proved to be a very, very effective tool," Xinhua news agency quoted White House Press Secretary Sean Spicer as telling the media on Tuesday.

"The President is the most effective messenger on his agenda," he said, adding that tweeting had served Trump well during the 2016 presidential campaign.

Trump said in a tweet earlier on Tuesday: "Sorry folks, but if I would have relied on the Fake News of CNN, NBC, ABC, CBS, washpost or nytimes, I would have had ZERO chance winning WH."

Trump has also attacked London Mayor Sadiq Khan, calling him "pathetic" in the wake of the London terror attack, as well as Qatar, hinting the Muslim country may have sponsored radical ideology.

Trump's tweets have become the target of mockery for his opponents.