US President Barack Obama is expected to meet world leaders, including the leaders of China, Japan and South Korea, at a summit on Thursday in Washington. The summit on nuclear security will also be discussing the growing tensions in the Korean peninsula and the South China Sea.

The summit will be the US president’s final drive towards international actions against the spread of materials that could be used to make atomic bombs or dirty weapons. Other critical issues will also be discussed besides the main agenda.

Obama is expected to meet Chinese President Xi Jinping privately the sidelines of the summit. Jinping is the only leader Obama will be holding a private meeting with during the summit, the New York Times reported.

The meeting with Jinping underlines China’s emergence as a dominant player in Asia and the determination of the US to keep its influence going strong in the Pacific. However, the US-China relationship is at its lowest point in 15 years, with the latter’s attempts at military expansion in the South China Sea being the main point of disagreement. However, China is facing a slowing economy and trade with it is being used as a driving point in the US presidential campaigns.

The US president will also be meeting Japanese Prime Minister Shinzo Abe and South Korean President Park Geun-Hye, as Washington seeks to build unity with its core allies in the wake of growing threat from the North Korea.

China, the traditional ally of North Korea, will be urged to use the UN sanctions it signed up to against the Pyongyang.

Deputy Secretary of State Antony Blinken said on Tuesday that if North Korea continues to make progress in its nuclear weapons program, the US will be left with no option but to take defensive measures, which China may not like.

“The bottom line remains that as long as North Korea continues in this direction, advancing its nuclear program, advancing its missile program, we are going to have to take these steps to defend ourselves and to defend our partners,” Blinken was quoted as saying by the ABC News.