A top Taiwanese missile official was found dead in a hotel room on Saturday morning after suffering a heart attack, according to the country’s official Central News Agency (CNA).

Ou Yang Li-hsing was deputy head of the National Chung-Shan Institute of Science and Technology, which is owned by the Taiwanese military and is the defense ministry’s research and development unit.

Taiwanese authorities said there was no sign of an “intrusion” in the hotel room in southern Taiwan where the 57-year-old died, according to CNA. He was in charge of supervising various missile production projects. Ou Yang’s family said he had a history of heart problems and also had a cardiac stent.

His death comes amid increased tensions between Taiwan and China following Speaker of the House Nancy Pelosi‘s visit to the island, which China considers part of its sovereign territory.

China has been carrying out live-fire military drills near Taiwan as part of its response to Pelosi’s visit, which the Chinese government strongly condemned.

Ou Yang had taken up the role at the military research and development unit earlier this year as the organization aims to more than double its missile production capacity to around 500 in 2022.

That increase in production capacity is reportedly in response to what Taiwan views as a growing military threat from China. Chinese forces have been conducting live-fire exercises near the island following Pelosi’s visit.