Ukraine has said the 6 September blast, which killed at least 16 people, was caused by a Russian missile.
It quoted air defence experts as saying missiles such as the one that hit Kostiantynivka can go off course for a variety of reasons, including an electronic malfunction or having a guidance fin that is damaged or sheared off during launch. The New York Times also cited evidence showing that minutes before the strike, the Ukrainian military had launched two surface-to-air missiles towards the Russian front line from the town of Druzhkivka, 16km northwest of Kostiantynivka.
The newspaper said measurements of holes caused by the explosion and fragments found at the scene were consistent with the 9M38 missile, which is fired by the mobile Buk anti-aircraft vehicle.Reuters could not independently verify the report. A Ukrainian presidential aide did not immediately respond to requests by Reuters for comment.