SEOUL, South Korea — North Korean officials returned to work at a joint inter-Korean liaison office on Monday, just three days after North Korea pulled its staff members from the office it has operated with South Korea since last September.

North Korea abruptly withdrew workers from the liaison office, located in the North Korean border town of Kaesong, last Friday, raising fears that its was hardening its position toward the South weeks after the summit meeting between its leader, Kim Jong-un, and President Trump, ended without a deal.

But several North Korean officials showed up in the office on Monday, telling their South Korean counterparts that they have returned to work “as usual,” the South’s Ministry of National Unification said in a statement. The North Koreans returned to the office two days after Mr. Trump tweeted that he had ordered his government to withdraw “additional large scale sanctions” against the North, though it was not clear whether the two moves were connected.

The unification ministry said it expected the operation of the inter-Korean official to return to normal. But the North Koreans did not explain why they withdrew from the office on Friday, or why it then reversed its decision.