Mikheil Saakashvili, the former Georgian president, has been stripped of his Ukrainian citizenship, Ukraine's migration service has said.
Mr Saakashvili, a former ally of Mr Poroshenko, is currently abroad. He vowed to fight for his rights.
He was made a Ukrainian citizen in 2015 and appointed governor of the southern Odessa region. He quit last year.
In a statement (in Ukrainian) on Wednesday evening July 26,2017, Ukraine's migration service said that "according to the Constitution of Ukraine, the president takes decisions on who is stripped of Ukrainian citizenship based on the conclusions of the citizenship commission".
It did not provide the exact reason, but stated that this could be done if a Ukrainian national acquired citizenship of another country or submitted false documents.