No proof is given. The OSCE Special Monitoring Mission to Ukraine (SMM) regularly releases reports on ceasefire violations. The official website of OSCE SMM does not confirm any information about Ukrainian soldiers laying mines in Donbas.

The article also provides a screenshot from a video which in fact, is a screenshot from a video uploaded in 2015. The video was created by the Turkish company Haci Productions for the Ukrainian Armed Forces as a thank you for the video created by the Ukrainians for the Turkish Air Force.

The Kremlin has long been spreading this type of disinformation. See similar disinformation case here. Unconfirmed information about Ukrainian soldiers seen laying mines was also spread in 2018. More information can be found here.