A herd of 15 elephants has wreaked havoc in China, trampling crops and causing more than a million dollars' worth of damage, after the animals escaped from a nature reserve last year.

The elephants have made a 500-kilometer (311-mile) journey through the southwestern province of Yunnan from the nature reserve in Xishuangbanna to Yuxi, a city of 2.6 million people, leaving a trail of destruction in their wake, according to state news agency Xinhua.

The creatures have also caused significant disruption to locals. Last Thursday, residents were told to stay indoors and pedestrians and vehicles evacuated in the town of Eshan after the elephants roamed the streets for six hours.

Authorities established a 24-hour command center to monitor the animals after they were seen in the Hongta District of Yuxi on Monday, with over 360 people, 76 police cars and dirt trucks and nine drones mobilized for the task, and 18 tonnes of elephant food prepared. No casualties have been reported, according to Xinhua.

Monitoring images show the herd is comprised of six female adults, three male adults, three sub-adults and three calves.

Asian elephants are the largest land mammal on the Asian continent, according to the World Wildlife Fund. They are considered a protected species in China, and around 300 of them live in Yunnan, according to Xinhua.