A pet mouse grounded a plane in China after it escaped from a passenger's pocket.

The mouse was taken on board by a female passenger, Liu Yulian, who hid it in her coat pocket and smuggled it past airport security.

"I went to sleep, and after I woke up, I found the mouse had gone missing. So I contacted the crew to see if they could help," says Liu.

The crew kept the information secret to avoid alarming other passengers but landed at Xiaoshan International Airport, reports the Today Morning Press.

"Upon landing, we quarantined the airplane, and searched it intensively five times, with no result," says the airport spokesman.

After two and a half hours, the airport lifted the quarantine and allowed the plane to fly on to its final destination, Shenzhen.

Passengers were unhappy and some are threatening to sue the airline for causing the delay by failing to stop the mouse from being brought on to the plane.

"We had to wait there a long time without getting out because of a security mistake," one passenger said.

The plane took off from Dalian Airport where officials have promised to tighten procedures.

A spokesman for airline, China Southern, says it acted in passengers' interest: "We couldn't continue to fly without getting rid of the potential danger."