BANGKOK — A group of 20 foreign diplomats who visited Myanmar’s Rakhine state, where half a million ethnic Rohingya Muslims fled recent violence, have urged the government to allow access by humanitarian groups and by a United Nations fact-finding mission to investigate allegations of human rights violations.

But the president’s office spokesman, Zaw Htay, told The Associated Press on Tuesday the government will stick by its earlier decision to bar the U.N. mission. It has said the group, assembled after similar violence last October, is interfering in Myanmar’s affairs.

The diplomats, taken Monday on a guided government tour of the affected area, said in a joint statement that there is a dire need for humanitarian aid.

The crisis in Rakhine has drawn international concern because of the exodus of more than 500,000 Rohingya to neighboring Bangladesh in just a month’s time. The violence began when the army retaliated for raids on government security posts on Aug. 25 by the Arakan Rohingya Salvation Army, an insurgent group.

Human rights groups charge that the army has abused and killed civilians and burned down thousands of homes. Rohingya are considered by many in Buddhist-dominated Myanmar to have poached land after immigrating illegally from Bangladesh. Advocates for the Rohingya insist many families have lived on the land for generations.

The diplomats’ statement condemned the insurgents’ initial attacks as well as the violence that followed it.

“We saw villages which had been burned to the ground and emptied of inhabitants. The violence must stop,” it said. “The security forces have an obligation to protect all people in Rakhine without discrimination and to take measures to prevent acts of arson.”

They also said they encouraged the Myanmar government “to move quickly to enable the voluntary, dignified and safe return to their places of origin of the hundreds of thousands of refugees who have fled to Bangladesh.”

“We saw on our visit the dire humanitarian need. We call once more for unimpeded humanitarian access to northern Rakhine and resumption of life-saving services without discrimination throughout the state,” they wrote.

Representatives of U.N. agencies were also on Monday’s tour.

In a separate letter, the U.N. office in Myanmar said the visit “was a positive step and such visits, under appropriate conditions, could help in our efforts to explore potential areas where the U.N. could cooperate with the Myanmar authorities in alleviating the dire situation in northern Rakhine.”

It expressed concerns similar to those of the diplomats.

It said the U.N. delegation “reiterated the need for a greater access for humanitarian and human rights actors to conduct comprehensive assessments of the situation on the ground in order to address the concerns and needs of all communities in affected areas,” and called for unfettered media access and for the safe and sustainable return of the refugees to their areas of origin.