China and Japan have agreed to jointly explore part of the gas deposits in the East China Sea, Foreign Ministry spokeswoman Jiang Yu said Wednesday.

This is the first concrete agreement the two countries have reached to explore undersea resources.

The agreement is part of the two sides' recent efforts to improve their relations, which have warmed considerably over the past two years.

As the first step, the two countries will conduct joint exploration in an area chosen by both.

The two countries have also agreed to continue consultations on possible joint explorations in other parts of the sea.

Chinese enterprises welcome Japanese firms to jointly explore the Chunxiao oil and gas field in accordance with China's laws on cooperation with foreign firms to explore offshore petroleum resources, Jiang said in a statement.

The two sides will hold detailed talks before signing a formal treaty.