Asia-Pacific markets fell after U.S. President Donald Trump said Tuesday that he had struck a preliminary trade agreement with Indonesia, which will impose a 19% tariff on the country's exports to the U.S.

Indonesia's central bank is set to release its policy decision later in the day.

President Donald Trump on Tuesday said he reached a preliminary trade deal with Indonesia, which will set a 19% tariff on the Southeast Asian country's U.S. exports.

"We will pay no tariffs. So they are giving us access into Indonesia, which we never had," Trump told reporters outside the White House.

"That's probably the biggest part of the deal. And the other part is they are going to pay 19%," he said.

It was not immediately clear if Jakarta had approved the deal terms as described by Trump. The Indonesian Embassy in Washington, D.C., did not immediately respond to CNBC's request for comment.

Asia markets started the trading day lower.

Japan's benchmark Nikkei 225 was flat at the open, while the Topix slipped 0.11% as of 8.04 a.m. local time (8.04 p.m. ET Tuesday).

South Korea's Kospi lost 0.5% and the small-cap Kosdaq was 0.56% lower.

Australia's S&P/ASX 200 declined 0.82%.

Source: CNBC