BANGKOK (AP) — Ethnic Karen guerrillas said they captured a Myanmar army base on Tuesday near the border with Thailand, representing a morale-boosting action for those opposing the military’s takeover of the country’s civilian government in February.

Myanmar’s military staged airstrikes several hours later on villages in territory controlled by the Karen forces, according to a guerrilla spokesman, a senior Thai official and a relief worker.

The fighting took place three days after a meeting of Southeast Asian leaders to try to hammer out a plan to restore peace in Myanmar, where the military government has attempted to suppress widespread opposition to its rule through the use of lethal force. More then 700 protesters and bystanders have been killed by security forces, according to several detailed estimates. The junta’s figure is about one-third of that.

A spokesman for the Karen National Union, the minority’s main political group seeking greater autonomy from Myanmar’s central government, said its armed wing attacked the base at 5 a.m. and burned it down just after dawn.

Casualty figures were not yet known, the KNU’s head of foreign affairs, Padoh Saw Taw Nee, said in a text message. There was no immediate comment from Myanmar’s military government.

The KNU, which controls territory in eastern Myanmar near the Thai border, is a close ally of the resistance movement against the military coup that ousted the elected government of Aung San Suu Kyi. Its armed wing is called the Karen National Liberation Army.

Video shot from the Thai side of the border showed flames rising from the government position on the banks of the Salween River amid the sound of heavy gunfire. The river marks the border with Thailand.

Padoh Man Man of the KNLA’s 5th Brigade, which launched the morning attack, said Myanmar’s military carried out airstrikes in the early afternoon, but he did not know how many casualties there were. He described the air raids as a “heinous war crime” and called for the international community to pressure the junta to stop them.

Sithichai Jindaluang, the governor of Thailand’s Mae Hong Son province, confirmed at a news conference that Karen guerrillas had overrun the Myanmar base and said a woman on Thai soil was wounded by a stray bullet. He said about 450 villagers have been evacuated from Mae Sam Lap for their own safety.

Sithichai also said a Myanmar military aircraft later bombed a Karen village.

Dave Eubank of the Free Burma Rangers, a humanitarian aid group with extensive experience in the area, said he could confirm there had been airstrikes on Karen villages in Papun district. He said five bombs were dropped but caused no casualties. Myanmar’s army was also staging ground attacks in the area, Eubank said.

Fighting between the KNU’s armed wing and Myanmar’s military has been intense since February.

Myanmar jets have bombed and strafed Karen villages since March 27, and its army has deployed new battalions to the area, in possible preparation for a large-scale offensive.

Up to 25,000 villagers have fled their homes and are hiding in jungles and caves, according to Eubank.

In response, the KNLA has kept up guerrilla attacks on Myanmar patrols and bases. The KNU has also given shelter to activists against military rule who have fled the government’s crackdown on the resistance movement in the cities.

There is a similar situation in northern Myanmar, where the Kachin minority says it has captured several government outposts and has been the target of air attacks.

The Karen and the Kachin are two of the bigger minority groups that have been seeking greater autonomy for decades, during which there have been periods of armed conflict punctuated by cease-fires.

The city-based resistance movement against the ruling junta has wooed the ethnic guerrilla groups in hopes that they can form a federal army as a counterweight to the government’s armed forces. A parallel National Unity Government established by elected lawmakers prevented from taking their seats by the army has appointed representatives of several minority groups to ministerial posts.

On Tuesday, a flash mob of anti-military protesters surged through an area of Yangon, Myanmar’s biggest city, for the second successive day to show fleeting but unyielding defiance of the ruling junta.

Such open protests have become less frequent since a brutal crackdown by the security forces began, but activity has picked up following Saturday’s meeting of the Association of Southeast Asian Nations in the Indonesian capital, Jakarta, with junta chief Senior Gen. Min Aung Hlaing in attendance.

The meeting prompted some guarded optimism after it issued a statement reporting a “five-point consensus” on Myanmar’s crisis. It called for the immediate cessation of violence, a dialogue among all concerned parties, mediation of the dialogue process by an ASEAN special envoy, provision of humanitarian aid through ASEAN channels, and a visit to Myanmar by the special envoy to meet all concerned parties.

However, a statement from the junta about the meeting published in Tuesday’s state-run Global New Light of Myanmar newspaper made no mention of the consensus statement. It emphasized that Myanmar would “give careful consideration to constructive suggestions made by ASEAN Leaders when the situation returns to stability in the country since priorities at the moment were to maintain law and order and to restore community peace and tranquility.”