TAIPEI (Taiwan News) — Eleven people have died in Taipei over two days from heart failure after a cold snap swept through the city between Saturday (Dec. 16) and Sunday (Dec. 17).

CNA reported that the majority of the deceased were elderly, and all died from sudden heart failure. According to the Taipei City Fire Department, four people died on Saturday and seven on Sunday.

Taiwan’s Central Weather Administration issued cold temperature warnings for the north on Sunday and said temperatures would drop as low as 10 C. Temperatures dropped sharply in the north over the two days, down from over 30 C on Friday.

The fire department said that although it had not been proven that the deaths were directly linked to the cold weather, it warned the elderly (aged over 65) and those with heart conditions to beware of the situation. The department said large fluctuations in temperature can cause sudden strokes and heart problems.

The fire department also reminded people to accompany vulnerable family members and friends to make sure they are safe and cared for.