Ukrainian President Petro Poroshenko has dissolved parliament and called snap elections, while the Ukrainian military clashed with separatist forces in armored vehicles that crossed from Russia and headed to the port of Mariupol.

The tanks and personnel carriers crossed into southeastern Ukraine on Monday, near the Sea of Azov, south of the rebel-held city of Donetsk.  This is territory held by Government forces, and - if true - this Russian move marks the first time the Moscow directly challenged Kiev, rather than act through ethnic Russian separatists in the east.

Russian Foreign Minister Sergei Lavrov claimed he had not heard the reports of the Russian hardware crossing into Ukraine, but complained of regular “disinformation about our 'incursions”.

In Kiev, President Poroshenko said too many members of the current parliament are holdovers who supported his ousted predecessor Viktor Yanukovich, and dissolved parliament.  Poroshenko is calling new elections on 26 October, he says because the majority of Ukrainians wanted a new parliament.

All of this happened on the eve of Tuesday’s scheduled meeting of Poroshenko and Russian President Valdimir Putin in Minsk.