Two senior officials of China Eastern Airlines (CEA) have been suspended over the "flight returns" incident that affected more than 1,000 passengers in Yunnan Province, the company announced on Monday.

Yang Xu, general manager with CEA's Yunnan branch, and Li Mingdao, the Party secretary of the branch, were being investigated over the "flight returns" incident from March 31 to April 1, an official with the Yunnan branch's discipline inspection department told Xinhua.

In the two days, pilots on 21 flights returned to their departure points in Yunnan. Media reports said they were protesting for better pay and working conditions.

Whether the two chiefs would resume their posts or face penalty depend on the investigation results, said the official, who declined to give his name.

Li Yangmin, the Shanghai-based headquarters' deputy general manager, will replace Yang to act as the regional head.

CEA posted an announcement on its website on Monday, admitting that some of the pilots had deliberately turned their aircraft round in flight.

Pilots involved in the flight disruptions had been suspended, and further investigation is underway, according to the announcement.

The company apologized for the inconvenience caused, and pledged to severely punish those responsible and compensate passengers.

The online notice also acknowledged that there were weaknesses in the management, vowing to improve work and safeguard passengers' benefits.

The company originally claimed that the incidents were due to poor weather, despite the fact that flights with other airlines flying the same routes landed on schedule during the same period.

The airline's response sparked suspicion and anger among passengers who pressed for more convincing reasons.

The Civil Aviation Administration of China sent a team to investigate the case four days after the incident.