At approximately 09:15hrs on 24 January, the SMM in government-controlled Mariupol heard at its location incoming massed Multi-Launch Rocket System (MLRS) attacks from a north-east direction, consisting of an extremely heavy barrage lasting 35 seconds. Twenty minutes later the SMM received information from the Joint Centre for Control and Co-ordination (JCCC) in Mariupol and other sources, that shelling had occurred in the area of Olimpiiska Street, in Ordzhonikidzevskyi district, 8.5 km north-east of Mariupol city centre, approximately 400 metres from a Ukrainian Armed Forces checkpoint.
At 10:20hrs the SMM went to Olimpiiska Street and saw seven adult civilians dead. The SMM observed in an area of 1.6 km by 1.1 km, including an open market, multiple impacts on buildings, retail shops, homes and a school. The SMM observed cars on fire and windows facing the north-eastern side of a nine-storey building shattered. The SMM was able to count 19 rocket strikes and is certain there are more. Four hospitals and the emergency service in the city informed the SMM that at least 20 people died and 75 people were injured and hospitalized. Ten of the wounded were in a critical condition, according to a hospital representative.
The SMM conducted a crater analysis and its initial assessment showed that the impacts were caused by Grad and Uragan rockets. According to the impact analysis, the Grad rockets originated from a north-easterly direction, in the area of Oktyabr (19 km north-east of Olimpiiska Street), and the Uragan rockets from an easterly direction, in the area of Zaichenko (15 km east of Olimpiiska Street), both controlled by the "Donetsk People's Republic" ("DPR").
At 13:02hrs and 13:21hrs the SMM heard again incoming MLRS salvos lasting for eight seconds, from an easterly direction. At a distance of 300 metres the SMM saw smoke above the Ukrainian Armed Forces' checkpoint number 14 (8.9 km north-east of Mariupol city centre), just several hundred metres away from where the shelling had hit in Olimpiiska Street.