Sean McCormack, a State Department spokesman, said on Thursday that US financing of its military sales to Thailand is to be cut off along with US training for Thai military personnel.
"The United States continues to urge a rapid return to democratic rule and early elections in Thailand," he said.
US assistance for health programmes will continue, including funds to help prevent the spread of Aids and preparing for a possible bird flu outbreak, McCormack said.
The Thai military has enjoyed years of close ties to US armed forces in the Asia-Pacific region.
The White House has also hinted that so far inconclusive talks with Bangkok on a free trade agreement might also depend on a return to democratic rule.
The EU presidency, currently held by Finland, also reiterated its call for Thailand to return to democracy on Thursday following the coup and said it would keep a close eye on developments there.
"The European Union attaches great importance to Thailand's speedy return to democracy and constitutional order, legitimised by free and democratic elections to be held as soon as possible," the presidency said in a statement.
Thaksin Shinawatra, the civilian prime minister, was ousted in a coup on September 19 that followed months of political instability.
The actions of the new military-appointed government would be evaluated by the EU, particularly "in the area of human rights, including freedom of expression and freedom of assembly, as well as the military leadership's specific assurances to this respect", it said.
"The European Union emphasises that it is for the people of Thailand as a whole to decide upon Thailand's future government."