Thai military personnel stand guard overlooking the Moei river on the Thai side of the shared border with Myanmar
Thai military personnel stand guard overlooking the Moei river on the Thai side of the shared border with Myanmar AFP

Thai armoured cars patrolled the town of Mae Sot Wednesday as the deep boom of artillery thundered across the border in Myanmar, where the junta and an ethnic armed group fought for a second day near a vital trade hub.

Hundreds queued to enter Thailand at the immigration checkpoint in Mae Sot, many fleeing the newest round of fighting to test the junta's hold on power.

Thai soldiers took up positions underneath the friendship bridge linking the town with Myanmar trade hub Myawaddy, the silhouettes of their counterparts from the Myanmar army visible across the sparse 200 metres (220 yards) of dirt and dried river dividing the nations.

Above the soldiers, hundreds walked across the friendship bridge and into the safety of the kingdom.

"I'm scared, so I decided to cross to the Thai side," Khu, 49, from Myawaddy, told AFP as she clutched her pet dog to her chest.

She said she had obtained a visa to remain in Thailand for seven days but did not want to return until the fighting stopped.

A Thai soldier, beginning his watch and who declined to give his name, said the sounds of conflict were the most intense he had heard in fifteen years on the border with Myanmar's conflict-riven Karen state.

Jafal Sweardik, 14, had just crossed over with his family from near Myawaddy, where he said the sounds of artillery and gunfire had cast a shadow over Eid al-Fitr festivities at the end of the fasting month of Ramadan.

"It was horrible, very scary," he told AFP, adding he was looking forward to being reunited with family on the Thai side to share an Eid feast of curry and rice.

The number of people passing Thai immigration from Myanmar had increased to around 4,000 per day in recent days, an immigration official told AFP, up from the usual number of around 1,900.

He said authorities were reinforcing the number of immigration officials to address the possibility that arrivals would rise further in the coming days.

The clashes come with the junta reeling from a series of defeats in the north and west of Myanmar, leading some of its opponents to believe it can one day be toppled.

Fighters from the Karen National Union (KNU) said Saturday they had seized a military base around 10 kilometres (6 miles) west of Myawaddy, and that more than 600 soldiers, police, and their families had surrendered.

KNU fighters had clashed again with the military around Myawaddy on Wednesday, a KNU spokesman Padoh Saw Taw Nee confirmed to AFP.

The junta has not responded to requests for comment on the KNU claim of the surrenders at the Thingannyinaung base.

More than $1.1 billion worth of trade passed through Myawaddy in the 12 months to April, according to the junta's commerce ministry -- a vital source of revenue for the cash-strapped military.

Residents told AFP fighting started around Myawaddy on Tuesday, sending people fleeing across the border, but that KNU fighters did not appear to have entered the town.

"There was fighting the whole of last night and in the morning as well," a resident told AFP on Wednesday, requesting anonymity for security reasons, as they hid in a basement.

"We can hear artillery sounds and explosions from our place. Planes are flying over," they said.

"My mother and other siblings fled to Mae Sot this morning. I'm now guarding our house with my uncle."

A truck driver on the road to Myawaddy in Myanmar said he had heard planes flying and the sound of artillery fire on Wednesday.

He said other drivers told him that authorities in the town had blocked traffic from entering from the Myanmar side.

In neighbouring Thailand, one Mae Sot resident told AFP they saw eight Thai military vehicles heading towards the border on Tuesday night.

"Many people have entered Mae Sot from the other side [Myanmar]," they said.

"I saw many online posts looking for a place to stay."

Thailand shares a 2,400-kilometre (1,490-mile) border with Myanmar, with the clashes coming as the Thai foreign minister said Tuesday the kingdom was prepared to accept 100,000 people fleeing.

Prime Minister Srettha Thavisin and high-level Thai officials met earlier to discuss the border issue.

The number of people passing Thai immigration from Myanmar had increased to around 4,000 per day in recent days, immigration officials said
The number of people passing Thai immigration from Myanmar had increased to around 4,000 per day in recent days, immigration officials said AFP
Thai military personnel atop an armoured vehicle keep watch over the Moei river on the Thai side of the shared border with Myanmar
Thai military personnel atop an armoured vehicle keep watch over the Moei river on the Thai side of the shared border with Myanmar AFP
Myanmar nationals cross over into Thailand at the Tak border checkpoint in Thailand's Mae Sot district
Myanmar nationals cross over into Thailand at the Tak border checkpoint in Thailand's Mae Sot district AFP