Kiev, April 26 : Satellite imagery have identified the presence of a third mass grave in the outskirts of the besieged Ukrainian city of Mariupol, according to an investigative report. The Radio Free Europe/Radio Liberty report said the pictures by Planet Labs, a San Francisco-based Earth imaging company, showed the appearance of a 200-metre-long grave in the village of Staryi Krym, 5 km from the devastated south-eastern city. The first images taken on March 24 showed three trenches, one of them 60-70 metres long, Ukrayinska Pravda quoted the report as saying. Then on April 7, the pictures revealed that the trenches became longer, and some parts that were dug earlier were covered up. Eventually the latest images on Sunday, taken a month after the original image, showed the appearance of new trenches. The total length of the mass graves is now estimated to reach over 200 metres. Confirming the presence of the third mass grave, Mariupol Mayor Vadym Boichenko alleged that Russian troops "get local residents to help with the burials in exchange for food". The village of Staryi Krym was captured by the Russian forces on March 10. On April 21, the the Mariupol City Council announced that upto 9,000 citizens of Mariupol may have been buried in a 300-metre-long mass grave in Manhush, a village occupied by Russian troops and located less than 20 km away from the besieged port city. Citing satellite images by Maxar Technologies, which collects and publishes satellite imagery of Ukraine, the Council had said that the "size of the mass grave in Manhush is 20 times that of the one in Bucha". A similar mass grave was recorded by a satellite in the village of Vynogradne near Mariupol. Earlier this month, Maxar images of the town of Bucha outside Kiev appeared to show bodies of civilians lying in the street nearly two weeks before the Russians left the town as part of a withdrawal from northern Ukraine. Bucha Mayor Anatoliy Fedoruk had said that least 300 civilians were killed in the town. /IANS