US senators seek release of more than $15 billion in Taiwan security support.

The senators' letter cited $300 million in foreign military financing, $1 billion that Congress directed the Defense Department to obligate, and a $14 billion package of foreign military sales awaiting approval.

The State and Defense departments did not immediately respond to Reuters' request for comment. China has repeatedly opposed US arms sales to Taiwan, while US law provides a framework for supplying Taiwan with defensive capability.