A senior State Department official says the United States is reviewing aid to Thailand following the military coup that toppled the government of Prime Minister Thaksin Shinawatra. Assistant Secretary of State for East Asian Affairs Christopher Hill discussed the issue with regional colleagues on the sidelines of the U.N. General Assembly in New York.

The State Department has said there is no justification for the Thai military coup, and Assistant Secretary Hill says the aid review is mandatory under various U.S. laws governing foreign assistance programs.

The senior State Department official spoke to reporters after attending, with Secretary of State Condoleezza Rice, an eight-nation meeting on northeast Asian security issues that was otherwise dominated by the North Korean nuclear issue.

Hill said the United States is monitoring developments in Bangkok closely and considers the overthrow of the civilian government a sad development for Thailand, which has been a long-standing U.S. ally in the region:

"We have made very clear in our statements that we consider this military move to be a step backward for Thai democracy, a very sad development for Thai democracy," he said. "We are also reviewing our assistance to Thailand in light of the various legal implications of assistance to a country in which there has been a military coup to depose a civilian elected leadership."

U.S. aid to Thailand is wide ranging and includes various economic and military programs. Assistant Secretary Hill said he had no immediate announcement of punitive action.

The White House said Wednesday all aspects of the relationship were under review and that negotiations on a free trade agreement with Thailand depended on a restoration of democracy.

Spokesman Tony Snow said the Bush administration hopes the coup leaders make good, swiftly, on their promise to restore civilian rule.

The country's military leaders have promised to appoint an interim prime minister within two weeks and hold new elections within a year.

Prime Minister Thaksin was in New York attending the opening of the U.N. General Assembly when the coup occurred.

He flew to London Wednesday without meeting Secretary Rice or other senior U.S. officials attending the events here.