SEOUL (Reuters) - North Korean workers are operating in the Kaesong industrial zone, state-run web sites said on Friday, after the joint venture with South Korea was suspended last year amid disagreement over the North’s nuclear and missile programmes.

A South Korean security guard stands guard on an empty road which leads to the Kaesong Industrial Complex (KIC) at the South's CIQ (Customs, Immigration and Quarantine), just south of the demilitarised zone separating the two Koreas, in Paju, South Korea, February 11, 2016. REUTERS/Kim Hong-Ji

The South ended more than a decade of cooperation at the factory park on the North Korean side of the demilitarized zone (DMZ) after the North launched a rocket that put an object into orbit, closing the last remaining window of interaction between the two sides.

At the time, South Korea said it would no longer allow funds paid for Kaesong to be used in the North’s missile and nuclear programmes. Since then, a South Korean official has said there is no evidence that North Korea diverted wages paid to its workers by South Korean companies operating in the park to its weapons programmes.

“They do not even see our proud workers labouring vigorously working in the Kaesong industrial complex,” North Korea’s propaganda web site Meari (arirangmeari.com) said in a post dated Friday.

Another propaganda web site, Uriminzokkiri, said “it is nobody’s business what we do in an industrial complex where our nation’s sovereignty is exercised”.

U.S.-funded broadcaster Radio Free Asia reported on Monday that North Korean authorities were operating 19 clothing factories within the Kaesong complex without informing South Korean authorities, citing an unnamed source with knowledge of North Korean matters in China.

An official at South Korea’s Ministry of Unification said North Korea must not violate South Korean firms’ property rights within the complex, wire service Yonhap reported.

The ministry could not be immediately reached for comment.

Reclusive North Korea and the rich, democratic South are technically still at war because their 1950-53 conflict ended in a truce, not a peace treaty.

In recent weeks, North Korea has launched two missiles over Japan and conducted its sixth nuclear test, and may be fast advancing toward its goal of developing a nuclear-tipped missile capable of hitting the U.S. mainland.

U.S. Secretary of State Rex Tillerson said last weekend that Washington was directly communicating with Pyongyang on its nuclear and missile programmes but that Pyongyang had shown no interest in dialogue.

U.S. President Donald Trump later dismissed any prospect of talks with North Korea as a waste of time.