Beijing’s military is worried North Korea could soon conduct its fifth nuclear test.

SEOUL,  (UPI) — China is deploying troops along its border with North Korea, as Pyongyang could be preparing a fifth nuclear test ahead of its Seventh Party Congress in May.

The Information Center for Human Rights and Democracy, a nongovernmental organization in Hong Kong, announced Wednesday that Beijing has dispatched 2,000 soldiers along the border, South Korean news service Newsis reported.

China has previously deployed troops along its border with North Korea.

In January after Pyongyang announced a “successful” hydrogen bomb test, China reportedly sent 3,000 soldiers to its northeastern region, and also sent troops during the North-South land mine provocation last August. In late 2013, China also dispatched troops in response to the execution of Kim’s uncle-in-law, Jang Sung Taek.

The center also said more Chinese military personnel were stationed at two major observation posts, and the guards are acting as lookouts 24 hours a day.

Some of the troops are responsible for measuring the radioactive material that could be emitted in the event of a North Korea nuclear test, the Center said.

Relations between Beijing and Pyongyang have deteriorated since Kim Jong Un fully assumed power in 2012. North Korea has continued to announce tests of nuclear weapons even as Beijing has repeatedly urged the country to work toward denuclearization.

According to the Hong Kong-based organization, the fraying ties could have been a driving force in a Chinese decision to stop providing fossil fuels to the North. That decision was made around the same time North Korea’s Moranbong Band canceled its tour of China in December.

Kim had ordered the band’s return in response to Beijing, the center stated.

North Korea movements at its Punggye-ri nuclear site have raised concerns regarding Pyongyang’s plans for a test.

In Seoul, U.S. Deputy Secretary of State Tony Blinken and Cho Tae-yong, deputy chief of South Korea’s presidential national security office, agreed to strengthen pressure along different dimensions to force North Korea to change its nuclear strategy, Yonhap reported.