WASHINGTON (REUTERS) - The US State Department has approved a possible US$8 billion (S$11 billion) sale of F-16 fighter jets to Taiwan, the Defence Security Cooperation Agency said on Tuesday (Aug 20) in an official notification to Congress.

The sale being considered would be for 66 aircraft, 75 General Electric engines, as well as other systems, the agency said in a statement.

It said the sale serves US national, economic and security interests, and would help Taiwan maintain a credible defence.

China has already denounced the widely discussed sale, one of the biggest yet by the United States to Taiwan, which Beijing considers a renegade province.

It has warned of unspecified "countermeasures".

Senate Foreign Relations Committee chairman Jim Risch, a Republican, has welcomed the proposed sale of the Lockheed Martin F-16 jets.

"These fighters are critical to improving Taiwan's ability to defend its sovereign airspace, which is under increasing pressure from the People's Republic of China," he said in a recent statement.

Secretary of State Mike Pompeo told Fox News on Monday that US President Donald Trump notified Congress of the sale last week.

Mr Pompeo told Fox News the sale was "consistent with past US policy" and that the US was "simply following through on the commitments we've made to all of the parties".

In Taipei, President Tsai Ing-wen said the sale would help Taiwan build a new air force and boost its air defence capacity.

In a post on Facebook, Ms Tsai said she was grateful for Washington's "continuous support for Taiwan's national defense".

"With strong self-defense capacity, Taiwan will certainly be more confident to ensure the cross-strait and regional peace and stability while facing security challenges," she said.

Taiwan unveiled its largest defense spending increase in more than a decade last week, amid rising military tensions with China.