Donald Trump tweets on Democratic presidential debate

Washington: Republican US presidential frontrunner Donald Trump has taken to Twitter to assess his democratic rivals during their first presidential debate.

Trump has 4.54 million followers on Twitter. In one of the tweets he said: "Sorry, there is no STAR on the stage tonight."

The five Democratic presidential candidates who participated in debate were Hillary Clinton, Bernie Sanders, Martin O'Malley, Jim Webb and Lincoln Chafee.

When Bernie Sanders came out in defence of Hillary Clinton, Trump described this as a good move by him.

"The hardest thing Clinton has to do is defend her bad decision making including Iraq vote, e-mails etc," he said.

In his tweets, he made fun of the Democratic candidates.

"Malley, as former Mayor of Baltimore, has very little chance, he said.

"Can anyone imagine Chafee as president? No way," he wrote.

Trump said he expected most viewers to tune in to the debate for a few minutes and then fall asleep.

"All are very scripted and rehearsed, two (at least) should not be on the stage," he said.