There is one image that will haunt me after the infamous September 10 border crossing: a soldier from the Ukrainian border guard unit attacked from behind by one of former Georgian president Mikheil Saakashvili's supporters.
Mr Poroshenko vowed to punish those responsible for Mr Saakashvili's breach of the border, while observers said they feared the ugly political spat would hit Ukraine's worldwide image.
Saakashvili, who was president of Georgia until 2013, acquired Ukrainian citizenship in 2015 but was stripped of that in July after a bitter falling out with his former ally, President Petro O. Poroshenko of Ukraine. Saakashvili says the decision was politically motivated.
The stateless Saakashvili had initially meant to travel through the Krakovets border crossing where hundreds of supporters of his Movement of the New Forces party had gathered.
Saakashvili and a crowd of supporters are proceeding into Ukraine on foot after breaking through a line of guards on the Polish-Ukrainian border. "Instead of this, a crime has been committed, because there is a constitutional principle of inviolability of borders", Poroshenko said. He is an enemy of Ukraine just as he is an enemy of Georgia. According to the border police, 12 policemen and five border guards suffered in clashes with guards of Saakashvili. He arrived at the border by bus after an attempt to enter Ukraine by train failed when authorities blocked it from entering the country, AFP reports.
The failure to stop Mr Saakashvili from returning was an embarrassment for Kiev and another headache for a leader fighting a Russian-backed insurgency and trying to restart a struggling economy.
While in Warsaw on Friday, Saakashvili asserted that Ukraine was witnessing a roll-back of reforms and efforts to stem corruption, reiterating that he wanted to get back into politics. Ukrainian authorities in the border region tried to block Saakashvili's return - first by train, then by bus - but then he walked across the Ukrainian border at Shehyni in the midst of a crowd of his supporters.
After several hours of waiting, realizing that the train wouldn't leave with him on board after all, Mikheil Saakashvili made a decision to enter Ukraine by bus at the Medyka crossing.
The president said Saakashvili should have used Ukrainian courts to challenge the revocation. The 49-year-old is now wanted on criminal charges in Georgia, which he says were trumped up for political reasons. They definitely underestimated him and how far he can go and, therefore, didn't prepare a plan to handle a scenario of Saakashvili's return to Ukraine.