A Chinese military submarine designed for carrying nuclear warheads was seen surfacing in the Taiwan Strait.

The 11,000-ton “Jin class” submarine appeared alongside several warships as President Xi Jinping continues to expand China’s nuclear arsenal.

The submarine surfaced near fishermen in a popular fishing district around 5 am on Thursday.

It was reported to be in distress, remaining stationary on the water for several minutes before a second Chinese ship arrived to assist.

Both vessels then drifted towards mainland China, accompanied by other military ships. It is unclear what caused the submarine to surface or if it was armed, the U.S. Sun has reported.

The 135-meter-long submarine is estimated to cost $750 million (£590 million).

Written by B.C. Begley