Taiwan's army has selected Boeing Co. over Bell Helicopter to supply 30 attack helicopters in a deal worth more than $1.5 billion, a defense official said on Tuesday.

The deal still requires approval from Taiwan's parliament and the United States government, which has grown increasingly frustrated by a six-year delay by Taipei in approving a previous arms package.

The AH-64D is the most suitable investment choice for the future, Dai Kuang-chao, an army colonel told a defense ministry news conference.

In opting for the AH-64D Apache Longbow, Taiwan's military decided against the Bell AH-1Z Cobra, which are made by Bell Helicopter, a unit of Textron Inc.

Arms purchases from the United States are highly sensitive as China regards Taiwan as part of its own territory and has not ruled out taking Taiwan by force if it moved towards formal independence.

Ties with Washington had been strained over a delay of approval for an $18 billion arms package originally offered by the United States in 2001. Last month the parliament approved a fraction of the original amount.