The island's defence ministry reportedly said Thursday that the Taiwanese military chief of the general staff was missing, including other senior military officials, after a helicopter made an emergency landing in the northern part of Taiwan.

The ministry said a rescue mission was underway for the 13 people, including Air Force General Shen Yi-ming, the chief of the general staff, according to Reuters. Taiwanese authorities reportedly said that at least 10 people had been found alive. Three persons, however, reportedly remain missing.

The Taiwan News media outlet said, citing local officials, that the list of the passengers reportedly included Political Warfare Bureau Deputy Director Yu Chin-wen, new Deputy Chief of Logistics of the General Staff Headquarters Maj. Gen. Huang Yu-min, Deputy Chief of the General Staff for Communications-Electronics and Information Maj. Gen. Tsao Chin-ping and a reporter for the Military News Agency, along with Shen.

The ministry said that Shen and Chen had survived in the incident.

Taiwanese Defence Minister Yen De-fa arrived at the site to oversee the rescue operation.

According to local media, citing military officials, the UH-60 Black Hawk helicopter went missing at approximately 9:00 a.m. local time (01:00 GMT) in a mountainous area near Yilan City.

A cause of the emergency landing reportedly remains unknown.

The incident occurred a week before a vote on 11 Jan, when the island is expected to hold presidential and parliamentary elections.