SEOUL (REUTERS) - Cross-border freight train services between North Korea and China have been suspended after a series of Covid-19 infections in the Chinese border city of Dandong, the Yonhap news agency said on Friday (April 29).

Authorities in Dandong decided on the suspension at North Korea's request, the agency said, citing unidentified sources.

The suspension came less than four months after North Korea eased its years-long border lockdowns against the coronavirus that began early in 2020.

International aid groups say the strict lockdowns worsened economic problems and threatened food supplies to millions.

Authorities in Seoul, the capital of neighbouring South Korea, said they were keeping watch on the situation.

"The government is closely monitoring possible changes in related moves following Covid-19 cases in Dandong region," said an official of the unification ministry, which is charged with handling relations between the two countries.