US presidential candidate Donald Trump was "just plain wrong" to say that British Muslims are not reporting suspicious activity by extremists to the authorities, Home Secretary Theresa May has said.

The Republican front runner has come in for criticism since claiming in a TV interview that Muslim communities were not doing enough to stop attacks like the explosions in Brussels that left more than 30 people dead.

He told ITV's Good Morning Britain: "When they see trouble they have to report it. They are not reporting it. They are absolutely not reporting it and that is a big problem."

In response to the comments, Ms May told the Commons: "I understand he said that Muslims were not coming forward in the United Kingdom to report matters of concern. This is absolutely not the case - he is just plain wrong."

Mr Trump also said he would hit Islamic State "so hard you wouldn't believe it" if he is elected to the White House.

The group has claimed it was responsible for Tuesday's bloodshed in the Belgian capital.

Mr Trump said: "I would hit ISIS (another name for IS) so hard you wouldn't believe it and I would get the people over there to put up their soldiers because it's about time that somebody did it.

"But I would have such back-up like you've never seen before in terms of air power, air strikes etc."

The tycoon-turned politician caused controversy last year when he demanded a block on Muslims entering the US and claimed parts of London were "so radicalised" police were "afraid for their own lives".

More than half a million people put their names to a petition calling for Mr Trump to be banned from entering the UK.

Mr Trump denied he was racist, saying: "I'm not 'anti' anything; I'm just common sense, I say it like it is.

"I have great respect for Muslims, I have many friends that are Muslims.

"I am just saying there is something with a radicalised portion that is very, very bad and very dangerous."

Miqdaad Versi, assistant secretary-general of the Muslim Council of Britain, told the same programme Mr Trump's claims were "just not true".

He said: "What we have to recognise is when some of these statements are made that fuel this idea of bigotry and really fuel the thing that terrorists themselves want - that Muslims are apart from the West and cannot be seen as equal citizens - these things are not good for our society."

The Metropolitan Police's Deputy Assistant Commander Neil Basu said police had received "increasing volumes of calls" to a dedicated anti-terror hotline since it was established, which he said was a "measure of success".