North Korea and China held a groundbreaking ceremony on Wednesday morning at the site of a proposed joint development project on the island of Hwanggeumpyeong in the Amnok River.

Roughly one-thousand people attended the ceremony, including China’s Commerce Minister Chen Deming, the North Korean chairman of the joint investment committee Lee Chul.

North Korea is known to have given China rights to develop the island, which is four times the area of South Korea’s Yeouido Island business district, in the form of a 50-year lease. China will reportedly build light industry complexes in the Hwanggeumpyeong economic zone.

The two nations have been stepping up their drive for economic cooperation. Both are planning another groundbreaking for a road that will link North Korea’s Rajin and China’s Hunchun, on Thursday at the earliest.