WASHINGTON, Feb 16 (Reuters) - The top Republicans on U.S. congressional foreign affairs and armed services committees pressed Democratic President Joe Biden on Thursday to include $2 billion in military assistance grants for Taiwan in his upcoming budget request.

Representatives Michael McCaul and Mike Rogers, chairmen of the House of Representatives Foreign Affairs and Armed Services committees, and Senators Jim Risch and Roger Wicker, ranking Republicans on the Senate Foreign Relations and Armed Services committees, asked Biden to include up to $2 billion in Foreign Military Financing (FMF) grants for Taiwan in his proposed budget for the fiscal year ending in September 2024.

Congressional aides said they expect Biden to release the budget on March 9.

In a letter to Biden, the four lawmakers called China's build-up of its military capabilities and the recent incursion into U.S. airspace of a high-altitude surveillance balloon "a grave threat" to U.S. interests.

They stressed the need to support Taiwan, an independently ruled island that China views as a breakaway province.

"To stop these trends, the United States must act with urgency to defend itself and ensure our allies and partners have the capabilities they need to defend against the (Chinese Communist Party)," the letter said.

Congress late last year overwhelmingly approved legislation authorizing $10 billion - or $2 billion per year for five years - of annual FMF grants for Taiwan. However, a spending bill passed at the end of the year did not include the money to fund the program.

The White House did not immediately respond to a request for comment on the letter.