U.S. Defense Secretary Lloyd Austin. (Getty/Kyodo)

The United States will give additional security support to Taiwan, Defense Secretary Lloyd Austin told lawmakers on Tuesday, as the self-ruled democratic island is facing increasing military pressure from China.

According to U.S. media, President Joe Biden's administration is gearing up to provide a $500 million worth of weapons to Taiwan. Details on their type have not been revealed.

"The United States will soon provide significant additional security assistance to Taiwan," Austin said, based on the presidential drawdown authority that allows the United States to expedite security aid, including arms, to foreign countries.

Authorized by Congress last year, it has been used to send weapons to Ukraine for more than a year since Russia began its invasion.

"Beijing has increased its bullying and provocations in the Indo-Pacific. It's embarked upon a historic military buildup, including in space and cyberspace," the Pentagon chief said at a review hearing before Senate lawmakers, outlining Biden's proposed budget request for the Defense Department for fiscal year 2024.

The move was part of a longstanding commitment to Taiwan, helping it maintain a sufficient self-defense capacity, Austin said.

China sees Taiwan as a renegade province, to be reunited with the mainland, by force if necessary.

Last year, the State Department approved the sale of $108 million worth of spare and repair parts for tanks to Taiwan among other assistance.

Taiwan has been expressing displeasure since last year that the delivery of weapons from the U.S., including Stinger anti-aircraft missiles, has been slow.

Austin told lawmakers that he agreed with the view that a Russian victory will increase the probability of an attack by China on Taiwan.