The former Republican presidential nominee, said President Trump’s executive order to temporarily ban immigrants from seven Muslim-majority countries would cause complications around the world and was a plus for the terrorist faction.
Mr Trump’s policy places a 90-day blanket ban on all immigrants and visitors travelling from Iran, Iraq, Libya, Somalia, Sudan, Libya and Syria – and indefinitely prohibits access to Syrian refugees.
Detractors have said the ban will only aid ISIS and other jihadist groups' propaganda operations.
Speaking on Face the Nation on CBSN, Mr McCain said: “There’s so much confusion out there and published reports are that neither the Department of Homeland Security or the Justice Department or others were consulted about this before this decision was made.
‘Lumping Iraq with Iran, right now we have several thousand Americans who are fighting in Iraq against ISIS alongside Iraqi military men and women.
John McCain believes Trump's ban will aid ISIS propaganda
I think the effect will probably in some areas give ISIS some more propaganda
“The Battle of Mosul has taken an enormous toll on the Iraqi military. Is Iraq the same as Iran is? Of course not.
"It’s been a very confusing process, I’m glad that it’s a pause, but we’ve got to understand the ramifications of this kind of action.
“I think the effect will probably in some areas give ISIS some more propaganda. But I’m very concerned about our effect on the Iraqis right now. The dominant influence in Iraq today is not the United States of America, it’s Iran."
Mr Trump’s directive has caused outrage, but the President has said he is not sorry.
His press secretary Sean Spicer said: “He is not going to apologise for putting the safety of this country first and foremost.”
Being President Trump: Key Moments
Fri, January 27, 2017
Inside Donald Trump's first week in the White House.
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Trump speaks briefly to reporters as he arrives aboard Air Force One at Joint Base Andrews
Hundreds of thousands of US citizens have taken to the streets in protest against the move.
A petition in Britain to block the billionaire Republican’s state visit to the UK has attracted one million signatures while Labour leader Jeremy Corbyn suggested he should be banned.
It is now expected to be the subject of a Parliament debate, after cross-party MPs including Lib Dem leader Tim Farron and senior Tory MPs have shown their support.