WASHINGTON: US President Donald Trump said on Thursday that he’s having to make "tough phone calls" to stop countries taking advantage of the United States after a diplomatic firestorm over the abrasive nature of his conversations with leaders of Australia and Mexico, and a public warning to Iran."Believe me, when you hear about the tough phone calls I'm having -- don't worry about it. Just don't worry about it," Trump told a National Prayer Breakfast meeting in Washington. "We're taken advantage of by every nation in the world virtually. It's not going to happen anymore.""The world is in trouble, but we're going to straighten it out, OK? That's what I do - I fix things," Trump said in remarks about threats to religious freedom, amid consternation in diplomatic circles over his style, temperament, approach to some religions, and his dissing of allies.Nations far and near and adversaries old and new are suddenly having to contend with the Trumpian style of diplomacy after Mexico, Iran, and Australia were publicly scolded and scalded by the new US President this week.World leaders have often used social media to exchange polite birthday greetings, congratulatory messages, commiserations etc, but the Trump method involves stinging rebukes, dire warnings, and trashing opponents and adversaries, even in the international arena steeped in protocol. He has also begun disavowing pacts and agreements made by previous administrations.On Thursday, the US President re-opened an old adversarial front that had just been pacified by the previous Obama administration -- much to New Delhi’s relief advantage -- with a stern warning to Teheran, saying "Iran has been formally PUT ON NOTICE for firing a ballistic missile" and it "should have been thankful for the terrible deal the US made with them!"While the warning to Teheran on its missile tests had already been issued by his National Security Advisor Michael Flynn , Trump followed it up while virtually disowning previous US administration’s agreements with the country, saying "Iran was on its last legs and ready to collapse until the US came along and gave it a life-line in the form of the Iran Deal: $150 billion."Administration officials did not elaborate on what the "notice" meant and what would follow.Trump also repudiated an agreement reached by the Obama administration with Australia to take in 1250 refugees, calling it a ''dumb deal'' and saying he will re-examine it.The public disavowal of the diplomatic agreement with one of Washington’s staunchest allies came amid reports that Trump had abruptly ended a phone conversation with Australia’s Prime Minister Malcolm Turnbull on Wednesday after accusing him of trying to ship off the ''next Boston bombers'' to the United States.Trump reportedly told Turnbull that the conversation was "the worst call by far" he had taken that day, after the pleasant exchanges he had with Russian President Putin and three other world leaders.The US President himself confirmed the disagreement with Australia by tweeting "Do you believe it? The Obama Administration agreed to take thousands of illegal immigrants from Australia. Why? I will study this dumb deal!"Diplomats, even US diplomats, were quick to point out that the agreement involved around 1200 refugees, not "thousands of illegal immigrants", many of them persecuted minorities from Iran and Iraq. Many of them were shocked by the long term implications of the Trump style."#Australia may be the single most effective+loyal ally of the US This is no way to treat a true friend," said former Bush era diplomat Nicholas Burns, noting that Trump had berated allies such as #Australia, #Germany+#Mexico, "not a negative word about Putin's division of #Ukraine."The fracas with Canberra came days after Trump reportedly threatened to send US troops to Mexico to take care of "bad hombres" there, according to leaked White House transcripts quoted by Associated Press."You have a bunch of bad hombres down there. You aren’t doing enough to stop them. I think your military is scared. Our military isn’t, so I just might send them down to take care of it," Trump told Mexican President Enrique Pena Nieto.Some accounts characterized Trump’s tone as jocular, even as Mexico denied Trump made any such threat and insisted that there have been constructive conversation in the days after the US President disinvited Pena-Nieto, asking him to stay at home if he did not toe the US line on contentious issues.Trump’s style has freaked out the traditionalist diplomatic community and the commentariat in Washington that is used to a genteel approach.The flare-up could do "lasting damage to relations between the two countries and could drive Canberra closer to China, which has a robust trading relationship with Australia and is competing with Washington to become the dominant force in the Asia-Pacific region," the New York Times warned.