REFILE-UAE's biggest traffic accident kills 3, injures 277

(Fixes dropped numbers in headline)

ABU DHABI, March 11 (Reuters) - Three people were killed and 277 injured in the United Arab Emirates on Tuesday when dozens of cars and buses collided in thick fog in what could be the country's biggest traffic accident, police said.

Up to 20 cars burned in the pile-up during the morning rush hour on the main motorway between the UAE trade hub of Dubai and the capital Abu Dhabi, police said. So many cars were hit that police had yet to count them all.

The death toll could rise as other casualties were in serious condition, at least one of them critical, police said. Pictures showed charred wrecks, broken glass and metal strewn across the road, which was blocked for most of the day as police and rescue workers evacuated casualties and removed cars. Television footage showed vehicles ablaze in the road.

"I saw lots of ambulances, fire engines and smoke coming out of cars," said Jenny Bateman, a British witness.

The crash, which took place on a road where the speed limit is 120 km (75 miles) an hour, was made worse by the fact that several buses carrying labourers to work were on the road.

Police said 12 buses carrying some 300 workers in total were involved in the crash, which took place at 6 a.m. (0200 GMT). (Reporting by Lin Noueihed and John Irish; Editing by Stephen Weeks)