Territorial claims have become a stressful issue in East and South East Asia over the past few years.

Conflicts over territory include the Spratly and Paracel islands in the South China Sea. Countries dispute ownership and China continues to expand its footprint.

President Barack Obama and Chinese President Xi Jinping spoke about the issue during Mr. Xi’s state visit to the United States. At a joint news conference, President Obama repeated his concerns about the maritime territory.

“We did have candid discussions on the East and South China Seas. I reiterated the right of all countries to freedom of navigation and overflight and to unimpeded commerce.”

Mr. Obama said he repeated concerns to Mr. Xi about land reclamation in the South China Sea. He said China’s action of filling in land in disputed island areas makes it hard to resolve dispute peacefully with neighbors.

President Xi defended China's claim to the area. He said China’s construction work on artificial islands in the South China Sea does not target any country.