(Updates with Vietnam rice situation)
By Ed Cropley
BANGKOK, Aug 15 (Reuters) - Four people have been killed in flooding and landslides in Laos, where the Mekong river has hit its highest level in at least 100 years after several months of unusually heavy rain, officials said on Friday.
The government and ordinary people in the landlocked Southeast Asian country have been rushing to complete a 2.5 metre (8 ft) wall of sandbags to stop the chocolate-brown waters inundating the capital, Vientiane.
Police have closed roads leading to the riverbank to make it easier for trucks delivering sandbags, the official Vientiane Times reported.
"We’ve been fighting very hard day and night for four days, but after today the water level should recede," government spokesman Yong Chanhthalansy told Reuters in Bangkok.
The Mekong, which flows 4,350 km (2,700 miles) from the glaciers of Tibet to the rice-rich delta of southern Vietnam, hit 13.68 metres (44.88 feet) in Vientiane on Thursday, trouncing a high of 12.38 metres (40.61 feet) recorded in 1966, the worst floods in living memory.
That depth — measured roughly from the river’s lowest level in the dry season — could rise slightly on Friday before retreating, Yong said.
In Vientiane, a levee was built along the river’s northern bank after the 1966 flooding but has been overrun in places, causing flooding in parts of the city of 200,000, one resident said.
There was widespread flooding upstream, although the former royal capital of Luang Prabang had escaped any damage to its ancient Buddhist pagodas, Yong said.
Downstream, eastern Thailand and low-lying Cambodia, where the annual flooding of the Mekong is crucial to rice and fish production, are braced for major flooding as the water surge moves slowly south.
Cambodia’s capital, Phnom Penh, sits right on the bank of the river. Officials said they had warned people living near the Mekong in the provinces of Kompong Cham, Kratie and Stung Treng to move their families and livestock to higher ground.
"We are not worried today but will be three or four days from now," Hydrology Department director Mao Hak told Reuters.
The high waters will ultimately flow down into Vietnam, where at least 130 people were killed and 36 were missing this week after the worst floods in decades due to the remnants of a tropical storm.
Forecasters said the waters in the delta had risen to an initial alarm level two weeks earlier than last year, although it was likely to have little impact on rice production as most of the current crop had already been harvested. (Additional reporting by Ek Madra in Phnom Penh and Ho Binh Minh in Hanoi; Editing by Alan Raybould and David Fox)