More areas have been added to the list of places Aussies should “reconsider” going to, as tens of thousands of local people sought refuge as border fighting entered a second day, heightening fears of an extended conflict.

“Armed conflict between Thai and Cambodian forces along the Thai-Cambodian border has increased,” Smartraveller says.

“We now advise reconsider your need to travel to eight districts in the Chanthaburi and Trat provinces. Martial law has been declared in these areas.”

Chanthaburi is a town on the Chanthaburi River famous for growing durian.

Trat is Thailand’s eastern-most province, about 315km from Bangkok.

Earlier warnings were made against going to the areas of Buriram, Si Saket, Surin and Ubon Ratchathani provinces along the Cambodia border.

Smartraveller also warned Australians to reconsider their need to travel to the Cambodian border provinces of Preah Vihear and Oddar Meanchey.

The Cambodian provinces are just north of Siem Reap, a historic city globally famous for stunning temples such as Angkor Wat.

Smartraveller reports military strikes, violence and landmines and says there have been casualties.

Border crossings in the area are closed.

Call for end to conflict

The UN Security Council held an emergency meeting behind closed doors on Friday in New York, while Malaysia, which chairs the 10-nation regional bloc that includes both countries, called for an end to hostilities and offered to mediate.

The council did not issue a statement but a council diplomat said all 15 members called on the parties to deescalate, show restraint and resolve the dispute peacefully.

The council also urged the regional bloc, the Association of Southeast Asian Nations known as ASEAN, to help resolve the border fighting, the diplomat said, speaking on condition of anonymity because the meeting was private.

Cambodia’s UN Ambassador Chhea Keo told reporters afterward that his country, which called for the emergency meeting, “asked for immediate ceasefires, unconditionally, and we also call for the peaceful solution to the dispute.”

He responded to accusations that Cambodia attacked Thailand asking how a small country with no air force could attack a much larger country with an army three times its size, stressing, “We do not do that.”

UN Security Council urges restraint by both sides

Keo said the Security Council called for both sides to exercise “maximum restraint and resort to diplomatic solution” which is what Cambodia is calling for as well.

Asked what he expects next, the ambassador said: “Let’s see how the call can be heard by all the members there.”

Thailand’s UN ambassador left the meeting without stopping to talk to reporters.

The Thai Health Ministry said more than 58,000 have fled from villages to temporary shelters in four affected border provinces, while Cambodian authorities said more than 23,000 people have evacuated from areas near the border.

The latest flare-up in a long-running border dispute between the two countries has killed at least 19 people in Thailand — mostly civilians —while Cambodia confirmed its first fatality on Friday.

Thailand’s acting prime minister, Phumtham Wechayachai, said on Friday that Cambodia may be guilty of war crimes due to the deaths of civilians and damage caused to a hospital. He said Thailand had exercised the “utmost restraint and patience in the face of provocations and aggression” from Cambodia.

Tensions over a disputed border area erupted into fighting after a land mine explosion along the border wounded five Thai soldiers on Wednesday.

Clashes break out across border areas

The Thai military reported clashes early on Friday in multiple areas along the border, including near the ancient Ta Muen Thom temple claimed by both sides.

Associated Press reporters near the border could hear sounds of artillery from early morning hours.

The Thai army said Cambodian forces had used heavy artillery and Russian-made BM-21 rocket launchers, prompting what Thai officials described as “appropriate supporting fire” in return.

Thailand said six of its soldiers and 13 civilians were killed, including children, while 29 soldiers and 30 civilians were wounded.

Cambodia’s chief official in Oddar Meanchey province, Gen. Khov Ly, said a man died Thursday after a Thai rocket hit a Buddhist pagoda where he was hiding.

At least four civilians in the province were also wounded on Thursday.

The Cambodian Education Ministry claimed that on Friday two Thai rockets had hit a school compound in Oddar Meanchey but caused no injuries. It said all schools in the province have been closed.

The Thai army denied it targeted civilian sites in Cambodia, and accused Cambodia of using “human shields” by positioning their weapons near residential areas.

Thousands flee villages near the border

As the fighting intensified, villagers on both sides have been caught in the crossfire, leading many to flee.

Around 600 people took shelter at a gymnasium in a university in Surin, Thailand, about 80 kilometres from the border. Evacuees sat in groups, on mats and blankets, and queued for food and drinks.

Seamstress Pornpan Sooksai was accompanied by four cats in two fabric carriers. She said she was doing laundry at her home near Ta Muen Thom temple when shelling began on Thursday.

“I just heard, boom, boom. We already prepared the cages, clothes and everything, so we ran and carried our things to the car. I was frightened, scared,” she recalled.

Rattana Meeying, another evacuee, said she had also lived through the 2011 clashes between the two countries but described this flare-up as worse.

“Children, old people, were hit out of the blue,” she said. “I never imagined it would be this violent.”

At the nearby Phanom Dong Rak hospital, periodic explosions could be heard on Friday, and a military truck arrived with three injured Thai soldiers, including one who had both legs severed.

Thursday’s shelling shattered windows at one of the hospital’s buildings and damaged its roof.

In the neighboring Sisaket province, more villagers took their belongings and left homes in a stream of cars, trucks and motorbikes after they received an evacuation order on Friday.

Across the border in Cambodia, villages on the outskirts of Oddar Meanchey province were largely deserted. Homes stood locked, while chickens and dogs roamed outside.

Some villagers earlier dug holes to create makeshift underground bunkers, covering them with wood, tarpaulin and zinc sheets to shield themselves from shelling.

Families with children were seen packing their belongings on home-made tractors to evacuate, though a few men refused to leave.

A remote Buddhist temple surrounded by rice fields accommodated several hundred evacuated villagers. Women rested in hammocks, some cradling babies, while children ran about. Makeshift plastic tents were being set up under the trees.

Veng Chin, 74, pleaded with both governments to negotiate a settlement “so that I can return to my home and work on the farm.”

ASEAN chair calls for calm

The conflict marks a rare instance of armed confrontation between ASEAN member countries though Thailand has tangled with Cambodia before over the border and has had sporadic skirmishes with western neighbour Myanmar.

Malaysian Prime Minister Anwar Ibrahim said Friday that Thailand and Cambodia had agreed to a ceasefire and to withdraw their troops from the border, but requested more time before implementing the action, according to a report by Malaysia’s Bernama national news agency.

Anwar said he had spoken to both Cambodian leader Hun Manet and Thailand’s Phumtham and urged them to open space for “peaceful dialogue and diplomatic resolution,” while offering to have Malaysia facilitate talks.

UN Secretary-General Antonio Guterres has also called for restraint and urged both countries to resolve disputes through dialogue, according to U.N. deputy spokesman Farhan Haq.

It’s the latest flareup in longstanding border tensions

The 800-kilometre frontier between Thailand and Cambodia has been disputed for decades, but past confrontations have been limited and brief.

The last major flare-up in 2011 left 20 dead.

The current tensions broke out in May when a Cambodian soldier was killed in a confrontation that created a diplomatic rift and roiled Thailand’s domestic politics.

Things got worse when a land mine wounded five Thai soldiers on Wednesday, leading Bangkok to close the border and expel the Cambodian ambassador. The next day, clashes broke out along the border.