Unesco's World Heritage Committee has postponed a decision on Cambodia's development plan for the Preah Vihear temple partly because it submitted a graphical illustration instead of a map, says a source in the Thai delegation.

Other reasons for the committee's postponement include evidence that Cambodia had deployed heavy weapons in the temple, that the country had failed to submit relevant documents on time, and that a memorandum of understanding between Thailand and Cambodia over the disputed territory in the area had not been settled.

The WHC decided to delay its decision on the management plan until next year's meeting in Bahrain because Thailand and Cambodia were unable to find common ground.

Brazil, the host of the meeting, had mediated between the two countries for an hour before the decision to postpone was made.

" The use of the graphical illustration, instead of a real map, has suggested a possible intent to conceal details about the areas surrounding the temple," the source said.

The Thai delegation capitalised on this by supplying a map that shows the construction of a road by Cambodia in the disputed overlapping 4.6 square kilometre zone.

Under a 2002 memorandum of understanding between Thailand and Cambodia, both sides agreed not to carry out any work in the area pending a survey to officially demarcate the common land boundary.

According to the source, the delegation has also submitted photos of a Cambodian installation of heavy artillery and troops in the temple.

"The Thai delegation had three minutes to talk to each of the WHC members. Our evidence made them feel that Cambodia's case was incomplete," said the source.

The source also called on Thai authorities not to get carried away with the delay and be prepared for the next WHC meeting.

"Cambodia has already set up a special body known as the Department of World Heritage, and we should also have a body that is responsible for this matter. It may be a long battle," said the source.

Part of the success of the Thai delegation led by Natural Resources and Environment Minister Suwit Khunkitti should be attributed to three military officers who accompanied them on the trip: Lt Gen Thawatchai Samutsakhon, chief of the 2nd army corps, Lt Gen Niphat Thonglek, commander of border affairs attached to the Supreme Command, and Maj Gen Noppadol Chotisiri, deputy chief of the Army Survey Department.

Mr Suwit said yesterday the WHC's postponement of its decision on the site was partly because Cambodia had failed to submit its documents six weeks before the meeting as required.

As a result, the Thai delegation pointed out to the committee that it did not have enough time to study the proposal which could affect the country's sovereignty, Mr Suwit said.

He said the WHC acknowledged the problem and wanted both countries to work out a solution before it considered a management plan.

Meanwhile, Prime Minister Abhisit Vejjajiva yesterday pledged to direct necessary resources to examine Cambodia's management plan now that the WHC had postponed its decision on the matter.

He said concerned authorities would spend the next 12 months studying the proposal, so that Thailand is able to present an informed opinion to the WHC at its next meeting in Bahrain.

"Within a period of one year, we will look at Cambodia's document and come up with a comprehensive recommendation [to the WHC]. It will be different [next year]. We have a chance and we have to do our best," he said.

Mr Abhisit said the 2000 memorandum of understanding on the survey and land boundary demarcation Thailand signed with Cambodia was instrumental in the postponement.

According to Mr Abhisit, it was the memorandum that forced Cambodia into conceding that border demarcation had not yet been settled.

He said the issue should prompt Cambodia to review its decision to have the temple listed as a world heritage site and acknowledge the limitations that come with that designation.

Mr Abhisit said that before Cambodia's unilateral bid to register Preah Vihear temple as a world heritage site, both countries were able to use the site for economic benefit without incident.

As for the alleged encroachment into the disputed zone, he said the Foreign Ministry had already sent a message that Thailand expected Cambodia to respect the memorandum of understanding.

Mr Abhisit said authorities would look into reports about Cambodia's alleged encroachment.

Deputy Prime Minister Suthep Thaugsuban played down speculation about renewed tensions, saying the delay would allow both countries to work out border disputes.

He said that any disputes with Cambodia would be dealt with at the government level.

Defence Minister Prawit Wongsuwon yesterday said there was no need to dispatch more troops to the Thai-Cambodian border despite a report that two battalions and heavy artillery had been sent there.