The United States has approved military aid to Taiwan under a programme usually used to help sovereign states in a move likely to anger China, which claims the self-ruled democratic island as its own territory.

According to international media reports, the Department of State informed Congress on Tuesday of the $80m package, which is modest in comparison with recent military sales to Taiwan but marks the first time Washington has provided assistance to Taipei under the Foreign Military Financing (FMF) programme, which generally involves grants or loans to sovereign countries.

The announcement is likely to heighten tensions with Beijing, which has not ruled out the use of force to take control of Taiwan.

The US and China have had formal diplomatic relations for 50 years, but Washington remains Taiwan’s biggest backer. Legislation also requires that it supply the island with the weapons necessary for its defence, but these have usually been done on a trade basis rather than as direct aid.

The State Department insisted that the first-ever aid under the FMF did not imply any recognition of Taiwan’s sovereignty.

“Consistent with the Taiwan Relations Act and our longstanding One China policy, which has not changed, the United States makes available to Taiwan defence articles and services necessary to enable it to maintain a sufficient self-defence capability,” a State Department spokesperson said.

Taiwan’s defence ministry expressed gratitude. “The aid will help in regional peace and stability,” it said in a short statement.

Beijing has stepped up its military activities in and around Taiwan in recent years and sought to isolate the island diplomatically since Tsai Ing-wen, considered a “separatist” by China, was first elected president in 2016. The island is preparing for its next presidential election in January and Tsai’s deputy, William Lai, is currently leading the pack. Tsai and Lai both say the people of Taiwan should be the ones to determine their future.