Beijing has warned Washington of counter-measures after the United States announced a US$1.1 billion arms package for Taiwan.

The sale comes a month after House Speaker Nancy Pelosi visited the island, also angering Beijing.

China urged the United States to “immediately revoke" the arms sale, stressing that Taiwan is an inalienable part of its territory.

"It sends wrong signals to Taiwan independence separatist forces and severely jeopardises China-US relations and peace and stability across the Taiwan Strait," said Liu Pengyu, spokesman for the Chinese embassy in Washington.

"China will resolutely take legitimate and necessary counter-measures in light of the development of the situation," he added.

The package – the largest for Taiwan approved under President Joe Biden's administration – includes US$665 million for contractor support to maintain and upgrade a Raytheon early radar warning system in operation since 2013.

Taiwan will also spend US$355 million on 60 Harpoon Block II missiles, which can track and sink incoming vessels.

The deal also includes US$85.6 million for more than 100 Sidewinder missiles. (AFP)