The Ukrainian president characterised the incident as a potential precursor to a Russian invasion, and declared martial law along the border with Russia and in Black Sea coastal areas, which expired on 26 December 2018.[1][27] The Russian government called the incident a deliberate provocation by Ukrainian President Petro Poroshenko ahead of the 2019 Ukrainian presidential election.[3] The incident took place a few days before the 2018 G20 Buenos Aires summit. Western leaders referred to it when they spoke of sanctions against Russia.