South Korean President Lee Myung-bak flew to Uzbekistan Tuesday, the second leg of his three-nation tour of Central Asia.

Mr. Lee is expected to sign a gas development deal with Uzbekistan counterpart Islam Karimov worth $4 billion .

The South Korean president headed to Uzbekistan after completing a three-day visit to Mongolia, where he held talks with President Tsakhia Elbegdorj. South Korea's Yonhap news agency says the leaders signed an agreement to conduct joint exploration and development of uranium ore and rare earth minerals vital for high-tech products such as mobile phones and notebook computers.

Mr. Lee will conclude his trip with a visit to Kazakhstan.