The protected animals left a nature reserve in Yunnan about 17 months ago.

Since then they have made international headlines with an extraordinary 500km (300-mile) trek that has seen them wander through fields, towns and cities, eating millions of dollars worth of crops and damaging buildings.

As the herd approached settlements, people were temporarily relocated to prevent conflict as local residents tried to protect their crops and homes.

By June the animals had reached the outskirts of the provincial capital of Kunming.

Efforts to head them off and send them back to the Mengyangzi Nature Reserve initially failed but eventually the herd turned around and began to head home.

Wan Yong, who heads the team monitoring the elephants, told a news conference on Monday that the herd had crossed the Yuanjiang River and was continuing to head south.

Electric fences, bait and artificial roads have been used to ensure the animals followed the correct path.

By Sunday night the herd was about 200km (125 miles) from the reserve, the Associated Press reported.

Experts say it is unclear exactly why the elephants left their usual habitat to embark on the journey. Some have suggested an inexperienced leader may have led the herd astray, while others believe the elephants could have been searching for a new habitat.

The Asian elephant is an endangered species. China has only about 300 wild elephants, mainly living - like the wandering herd - in the south of Yunnan province.