MANILA (Reuters) - Leaders of Asian nations meeting in Manila on Monday skirted around the mass exodus of Rohingya Muslims triggered by Myanmar s military crackdown, disappointing human rights groups who were hoping for a tough stand on the humanitarian crisis. There was no pressure either from U.S. President Donald Trump over the Philippines  bloody war on drugs during a meeting on the sidelines of the summit with President Rodrigo Duterte. Trump told reporters that he had a  great relationship  with Philippines leader, who, a year ago, had branded then-President Barack Obama  a son of a bitch  for questioning his ruthless campaign.  They really hit it off,  Duterte s Communications Secretary Martin Andanar told reporters after the meeting with Trump. A draft of the statement to be issued after a meeting of Southeast Asian leaders made no mention of the flight of Rohingya from military operations in Myanmar s Rakhine state  that the United Nations has described as ethnic cleansing. One paragraph mentioned fleetingly the importance of humanitarian relief for  affected communities  in Rakhine state. The statement was drawn up by the Philippines, current chair of the 10-member Association of Southeast Asian Nations (ASEAN), which includes Myanmar. It did not use the term Rohingya for the persecuted Muslim minority, which Myanmar leader Aung San Suu Kyi has asked foreign leaders to avoid. The government in mostly-Buddhist Myanmar regards the Rohingya as illegal immigrants from Bangladesh and does not recognize the term. Over 600,000 Rohingya have fled to refugee camps in Bangladesh since military clearance operations were launched in response to attacks by Rohingya militants on Aug. 25. The plight of the Rohingya has brought outrage from around the world and there have been calls for democracy champion Suu Kyi to be stripped of the Nobel peace prize she won in 1991 because she has not condemned the military s actions. Some ASEAN countries, particularly Muslim-majority Malaysia, have voiced strong concern over the issue recently. However, in keeping with ASEAN s principle of non-interference in each others  internal affairs, it appeared to have been put aside at the summit.  With Myanmar having ethnically cleansed 600,000 Rohingya Muslims in just two months, it s time for ASEAN to transcend its do-nothing approach to atrocities among its members,  said  Kenneth Roth, executive director of Human Rights Watch, in a Twitter message. The ASEAN leaders did agree that they should not take a lull in the dispute over the South China Sea for granted.  While the situation is calmer now, we cannot take the current progress for granted,  they said in a statement drafted ahead of a meeting with Chinese Premier Li Keqiang.  It is in our collective interest to avoid miscalculations that could lead to escalation of tensions.  China claims almost all of the sea, one of the world s busiest waterways. Taiwan and four ASEAN nations - Malaysia, Vietnam, the Philippines and Brunei - have competing claims. Philippine President Rodrigo Duterte suggested ahead of the summit that, despite their differences, the leaders should not discuss the South China Sea.  We have to be friends. The other hotheads would like us to confront China and the rest of the world on so many issues,  he said on Sunday.  The South China Sea is better left untouched.  At the meeting s formal opening on Monday, he pointed to other triggers for a threat of violence in the region, including terrorism, violent extremism, and piracy on the seas.  The menace of illegal drug trade continues to endanger the very fabric of our society,  he said. More than 3,900 people have been killed in the war on drugs that Duterte declared when he took office last year. His government says the police act in self-defense, but critics say executions are taking place with no accountability. The United States and the Philippines, a former U.S. colony, have been strategic allies since World War Two. But their relations have been strained by anti-U.S. outbursts from Duterte and his enthusiasm for better ties with Russia and China. However, the animosity of the past appears to have been all-but forgotten, and Duterte - who has been called the  Trump of the East  for his brash style and coarse language - told the U.S. president:  We are your ally. We are an important ally.  Trump was criticized earlier this year after he praised Duterte during a phone call for the  great job  he was doing to counter illegal narcotics. The two leaders seem to have warmed to each other after meeting for the first time on Saturday at a meeting of Pacific Rim leaders in Vietnam. On Sunday, Duterte crooned hit Filipino love song  Ikaw  (You) at a gala dinner in Manila, saying it was on  the orders  of Trump. One of the song s verses begins:  You are the light in my world, a half of this heart of mine . On the last leg of a marathon Asia tour that has taken him to Japan, South Korea, China and Vietnam, Trump told reporters that he had made significant progress on trade issues.  We ve made some very big steps with respect to trade, far bigger than anything you know,  he said, describing his trip as fruitful and adding:  It was red carpet like nobody, I think, has probably ever seen.  