(Adds U.S. diplomat) By Aung Hla Tun YANGON, Nov 30 (Reuters) - The Myanmar junta has shut down a Yangon monastery which served as a hospice for HIV/AIDS patients and expelled its monks, an opposition lawyer said on Friday. "The authorities sealed Maggin monastery yesterday afternoon" and expelled the monks, said Aung Thein of detained democracy icon Aung San Suu Kyi's National League for Democracy. "The authorities did not give them any documents and did not say under which law the action was taken, so we cannot do anything to provide them with legal assistance," he added. United Nations special envoy Ibrahim Gambari criticised the closure of the monastery, which was used as a hospice for HIV/AIDS sufferers and a refuge for provincial patients who came to Yangon for medicines. "Any actions that run counter to the spirit of national reconciliation, any action that will undermine the dialogue between the government and those who disagree with the policy of the government should be avoided," Gambari said in Phnom Penh. "And I'd like to repeat that," he told reporters during a visit to Cambodia on a regional tour before returning to the former Burma next month for more talks with the government and probably Suu Kyi. The abbots of Maggin monastery have long had the reputation of supporting pro-democracy cam