The United States has ordered the departure of non-essential diplomats from Myanmar, amid growing violence following the military coup to oust civilian leader Aung San Suu Kyi.
Daily protests demanding the restoration of the elected government have been met with a military crackdown that has left more than 520 civilians dead in the weeks since the 1 February coup.
The junta's violent response has triggered international condemnation - and threats of retaliation from some of Myanmar's ethnic armed groups.
The US State Department said it was ordering the departure of "non-emergency US government employees and their family members".
The decision was taken to protect the safety and security of staff and their families, the State Department said.
World powers have repeatedly condemned the violent crackdown on dissent and hit top junta figures with sanctions.
But the pressure has not swayed the generals. Saturday, the annual Armed Forces Day, saw the biggest loss of life so far, with at least 107 people killed.
The situation has angered some of Myanmar's 20 or so armed ethnic groups, who control large areas of territory mostly in border regions.
Three of them - the Ta'ang National Liberation Army, the Myanmar Nationalities Democratic Alliance Army and the Arakan Army (AA) - yesterday threatened to join protesters' fight unless the military reined in its crackdown.
Two other groups - the Karen National Union (KNU) and the Kachin Independence Army (KIA) - have stepped up attacks on military and police in recent days.
A police station in Bago was reportedly hit with a rocket attack that injured five officers, though it was not clear who was responsible.
The KNU, one of the biggest rebel groups, took over an army base in eastern Kayin state at the weekend, prompting the military to respond with air strikes.
Around 3,000 people fled through the jungle to seek safety across the border in Thailand after the weekend strikes.
The Thai foreign ministry said about 2,300 have returned to Myanmar, while about 550 remain in Thailand.
The UN Security Council, of which Ireland is a member, will hold an emergency session on Myanmar today, requested by the UK.
The 15 members will meet behind closed doors, beginning with a briefing from the UN's special envoy on Myanmar, Christine Schraner Burgener.
