Burmese leader Aung San Suu Kyi has cancelled plans to attend the UN General Assembly, a government spokesman said as the country draws international criticism over violence against ethnic Rohingya Muslims.
The violence has killed hundreds and driven at least 370,000 Rohingya over the border into Bangladesh in less than three weeks.
Presidential office spokesman Zaw Htay said Ms Suu Kyi will skip the assembly, which opened on Tuesday and runs until September 25, to address domestic security issues.
While she is not Burma's president, her official titles are state counsellor and foreign minister, she effectively serves as leader of the south-east Asian nation.
The spokesman said President Htin Kyaw is in hospital so the second vice president will attend.
"The first reason (Suu Kyi cannot attend) is because of the Rakhine terrorist attacks," Zaw Htay said.
"The state counsellor is focusing to calm the situation in Rakhine state. There are circumstances.
"The second reason is, there are people inciting riots in some areas. We are trying to take care of the security issue in many other places.
"The third is that we are hearing that there will be terrorist attacks and we are trying to address this issue."
Attacks by an insurgent Rohingya group on police outposts on August 25 have set off a wave of violence in Burma's Rakhine state, with hundreds dead and thousands of homes burned - mostly Rohingya in both cases.
The government blames Rohingya for the attacks, but journalists who visited the region have seen evidence that raises doubts about its claims that they had set fire to their own homes.
Many of the fleeing Rohingya have said Burmese soldiers shot indiscriminately, burned their homes and warned them to leave or die in what the government has called "clearance operations". Others said they were attacked by Buddhist mobs.
Ms Suu Kyi, a Nobel Peace Prize laureate who lived under house arrest for many years under a junta that ultimately gave way to an elected government, faces international criticism and pressure.
On Tuesday, Iran's supreme leader Ayatollah Ali Khamenei called the killing of Muslims a political disaster and called Ms Suu Kyi a "brutal woman".
UN human rights chief Zeid Ra'ad al-Hussein said the Rohingya were victims of what "seems a textbook example of ethnic cleansing".