Trump toughens rhetoric against Muslim immigrants

The United States is "importing radical Islam" through a failed immigration system, Republican presumptive presidential candidate Donald Trump warned as he ramped up his rhetoric for a ban on Muslims entering the country.

"We need to tell the truth, also, about how radical Islam is coming to our shores. We are importing radical Islamic terrorism into the West through a failed immigration system - and through an intelligence community held back by our president," Trump, 69, said in a major policy speech on terrorism and national security.

His comments came two days after a New York-born self-radicalised Afghan-origin youth killed 50 people in the deadliest mass shooting in American history. In his speech in New Hampshire, Trump reiterated call for a temporary ban on Muslims entering the US and said that the Afghan family of the Orlando shooter should not have been allowed to enter America.

"We have a dysfunctional immigration system which does not permit us to know who we let into our country, and it does not permit us to protect our citizens. We have an incompetent administration, and if I am not elected President, that will not change over the next four years - but it must change, and it must change now," he said.

"With fifty people dead, and dozens more wounded, we cannot afford to talk around the issue anymore - we have to address it head on. I called for a ban after San Bernardino, and was met with great scorn and anger, but now, many are saying I was right to do so - and although the pause is temporary, we must find out what is going on," he said.

Trump said the ban will be lifted when "we as a nation are in a position" to properly and perfectly screen those people coming into the US.

Immigration laws give the President the power to suspend entry into the country of any class of persons that he deems detrimental to the interests or security of the country, he observed.

"I will use this power to protect the American people. When I am elected, I will suspend immigration from areas of the world when there is a proven history of terrorism against the United States, Europe or our allies, until we understand how to end these threats," Trump said.

"After a full, impartial and long overdue security assessment, we will develop a responsible immigration policy that serves the interests and values of America. We cannot continue to allow thousands upon thousands of people to pour into our country, many of whom have the same thought process as this savage killer," the billionaire from New York said.

Trump gave examples of several terrorists and their families entering the US through the immigration system.

"All of the 11 September hijackers were issued visas. Large numbers of Somali refugees in Minnesota have tried to join the ISIS. The Boston bombers came here through political asylum," he said.