SEOU - Some of the Democratic People's Republic of Korea (DPRK) officials returned Monday to the joint liaison office with the Republic of Korea (ROK) in the DPRK's border town of Kaesong, South Korea's unification ministry said.

The ministry said in a statement that a part of the DPRK staff came to the liaison office for shift work as usual early Monday morning.

Officials from the two sides had a meeting as usual in the morning, according to the ministry.

The liaison office, which opened last September for the round-the-clock communications between the two Koreas, would be in normal operation, the ministry said.

It came after the DPRK announced its decision Friday to withdraw all of its staff from the liaison office.

Asked about the reason for the DPRK's pullout decision, an unnamed unification ministry official told reporters that the ROK planned to figure it out later, according to the ministry.

The DPRK told the ROK that there has been no change in its willingness to operate the joint liaison office well in accordance with the joint declaration, made by the leaders of the two Koreas.

ROK President Moon Jae-in and top DPRK leader Kim Jong-un agreed to open the liaison office after their first summit last April in the truce village of Panmunjom.

ROK officials worked at the liaison office in Kaesong over the weekend and were normally at work in the office on Monday.

The DPRK's decision to withdraw from and return to the liaison office came after the second summit between Kim, the DPRK's top leader, and US President Donald Trump ended with no agreement in late February in the Vietnamese capital of Hanoi.

After the Hanoi summit, ROK's presidential Blue House said both the DPRK and the United States made it clear to continue diplomacy and negotiations.