U.S. Secretary of State John Kerry was to meet with Chinese Foreign Minister Wang Yi on Tuesday for talks expected to focus on ironing out differences over how strongly to sanction North Korea for its nuclear and missile tests.

For more than a month since the North's nuclear test, the U.S. Security Council has been struggling in negotiations to come up with a new sanctions resolution on the North because China has been reluctant to impose harsh measures on Pyongyang.

Amid the deadlock, the North flouted the Security Council again with a banned missile launch on Feb. 7.

Tuesday's meeting between Kerry and Wang will be watched closely for a breakthrough in the negotiations.

Beijing has condemned the North's nuclear and missile tests but has been lukewarm about calls for a stern response. Analysts have long said Beijing fears that pushing Pyongyang too hard could lead to its collapse, instability on its border and the ultimate emergence of a pro-U.S. nation.

Chinese cooperation is key to putting together any meaningful sanctions resolution and its implementation as it is one of the five veto-holding permanent members of the U.N. Security Council, and the main provider of food and fuel aid to the impoverished North.

Tuesday's talks also take place amid rising tensions between the two sides over China's vehement opposition to the proposed deployment of the U.S. THAAD missile defense system to South Korea to better defend against North Korean threats.

Wang could raise the THAAD issue during the talks with Kerry.

Shortly after the North's missile launch on Feb. 7, South Korea and the U.S. jointly announced they would begin official discussions on the possible placement of the U.S. Terminal High Altitude Area Defense (THAAD) missile defense system in South Korea.

China has claimed THAAD can be used against it, despite repeated assurances from Washington that the system is aimed only at deterring North Korean threats. Beijing expressed regret after the South and the U.S. announced the decision to hold THAAD talks. (Yonhap)