US President Barack Obama said on Thursday said that US and China will cooperate to prevent North Korea from carrying out any further nuclear tests. The decision was reached at a meeting between Obama and Chinese President Xi Jinping that was held on the sidelines of the nuclear summit in Washington.

“President Xi and I are both committed to the denuclearization of the Korean Peninsula and full implementation of U.N. sanctions,” the Time quoted Obama as saying in a statement on Thursday. “We’re going to discuss how we can discourage action like nuclear missile tests that escalate tensions and violate international obligations.”

Washington and China previously worked together in the negotiation of the stringent UN sanctions against North Korea. The sanctions were passed in March after it defied international laws by repeatedly carrying out nuclear tests.

In recent weeks, North Korea has performed hydrogen bomb tests and test-fired missiles. Hours after Obama and Jinping’s meeting in Washington, a news agency in South Korea reported that the North appeared to have test-fired another missile.

According to the news agency, the latest test appeared to be a ballistic missile that landed off the east coast of the Korean peninsula.

Chinese state news agency Xinhua reported that Jinping said it is crucial that all parties “fully and strictly” effectuate the newly-agreed sanctions, the BBC reported.

The US and China also issued joint statements vowing to cooperate in improving nuclear security and implementation of the climate change deal.

However, they differed in other areas of the issue. Jinping told Obama that China is firmly opposed to the deployment of a new missile defense system by the US in South Korea. He said that it would go against China’s national security interest and also affect the strategic balance of the region.

The US and South Korea are considering the deployment to deal with the threat posed by the North. China is also concerned that the deployment would allow the US radar coverage over the Chinese territory, the Yahoo News reported.