KIEV, April 28 (Reuters) - A forest fire in northern Ukraine threatened on Tuesday to spread towards the abandoned Chernobyl nuclear power plant (NPP) on Tuesday, Interior Minister Arsen Avakov said in a post on Facebook.

“At 1830 (1530 GMT) the situation with the forest fire around the Chernobyl plant escalated. The flames once again consumed the forest in the direction of the Chernobyl plant. Fire in the treetops and sharp gusts of wind seriously threaten to spread the blaze in the 20 km (12.4 mile) zone around the plant,” he said.

In 1986 a reactor fire led to an explosion at Chernobyl, causing the world’ worst nuclear disaster. Radioactive materials remain at the site, covered with a concrete casement that the Ukrainian authorities plan to replace by 2016.