Updated

China has expressed regret over South Korea's expansion of its air defense zone that partially overlaps with a similar zone declared by Beijing.

South Korea's move Sunday followed China's announcement of a similar zone believed aimed at claiming disputed territory. Beijing's zone has been criticized by its neighbors and the United States, who say they will not honor it.

The new South Korean zone covers a submerged reef that South Korea controls but that China also claims, and it enlarged parts of airspace also included in the Chinese zone.

Chinese Foreign Ministry spokesman Hong Lei said Monday that South Korea had informed Beijing of its expanded zone and called it "regrettable." He says China remains in contact with Seoul and hopes South Korea will "properly handle the issue."