With criticism growing that the international effort to rebuild Afghanistan was flagging earlier this year, President Bush was eager to announce that the United States, Japan and Saudi Arabia had agreed to donate $180 million toward the troubled effort to reconstruct the main Afghan highway.

Afghan President Hamid Karzai was at his side at the United Nations when Bush declared in September that the United States would donate $80 million and the two other countries would each give $50 million to build the road, which Karzai had called his top reconstruction priority.

Three months later, that promising beginning has turned acrimonious, as one of the announced partners apparently has changed its mind about its contribution.

According to U.S. and Afghan officials, the Saudi offer to give $50 million for the road repair has been changed to the offer of a low-interest loan of $30 million. But because Afghan officials are unwilling to take on national debt, they have rejected the Saudi offer, and the road-building project has slowed as a result.

"We are very disappointed that [the Saudis] have done this and that it has not been resolved or rectified," said Haron Amin, deputy chief of mission of the Afghan Embassy in Washington.

"It not only creates problems for construction of the road, but it sends a bad signal to the international community. This sends the entirely wrong message," he said.

Saudi officials declined to comment on the issue. U.S. officials, however, said, there appeared to be disagreement between Saudi officials in the United States and officials in the Saudi capital about the size and nature of their contribution.

The current impasse on the road-building funds is made more charged by the recent history of Saudi financial assistance -- both official and private -- for the former Taliban rulers of Afghanistan. The Saudis were key supporters of the Taliban as they came to power in the mid-1990s, and helped fund many of the Pakistani madrassahs, or religious schools, from which the Taliban sprang.

The issue is a sensitive one for the Bush administration, as well, because of its own complicated relations with the Saudis after the Sept. 11, 2001, terrorist attacks, and officials were reluctant to publicly discuss the dispute over the road-building money.

The U.S. Agency for International Development made clear last month, however, that there was a problem. In a progress update, the agency wrote that "Saudi Arabia still maintains the offer was a $30 million concessional loan, not a $50 million grant."

Western diplomats said last week that the issue remained unresolved, and that the United States was "leaning hard" on the Saudis to keep to the $50 million commitment. They said that the Saudi contribution was "memorialized" in a document that made clear the money would be in grant form, not as a loan.

According to U.S. officials, the difficulties with the Saudi money have had no impact on the U.S. road-building effort in Afghanistan. Road construction is now underway south of Kabul and will continue there until weather conditions make it impossible, according to Nicholas Masucci, CEO of the Louis Berger Group. That New Jersey firm recently was granted the contract to oversee the U.S. contribution to the road building.

The 600-mile highway, which runs south from Kabul to Kandahar, and then northwest to Herat, is the main road in Afghanistan. It was built with U.S. and Soviet help before the Afghan wars began, and has greatly deteriorated over the years. Karzai has said that reconstruction of the main highway is essential to jump-start the Afghan economy, and to show that foreign donors are serious about helping Afghanistan.

With suspicions about Saudi Arabia running high, some members of Congress quickly criticized the Saudis for their apparent turnaround on the Afghan road.

"While the Saudi regime supports dubious charities with alleged ties to terrorists, it shortchanges vital reconstruction projects in Afghanistan, a nation which has been ravaged by terrorists," said Rep. Tom Lantos (D-Calif.), the ranking Democrat on the House International Relations Committee. " It is outrageous that the wealthy Saudi regime is unwilling to provide meaningful assistance to a poor Muslim nation that has suffered so much."

U.S. officials have complained that many nations that pledged rebuilding funds for Afghanistan have been slow to deliver the money or to implement their programs.

An Afghan worker prepares asphalt to repair roads in Kabul. Repairing damaged roads will help the government and aid groups to deliver supplies.