"Saakashvili shouldn't have left the country", he told foreign reporters.
President Poroshenko has so far made no public comments on the issue.
In a video posted on Facebook overnight, however, Saakashvili said the decision was politically motivated. Poroshenko stressed Saakashvilis extradition was a purely legal issue and if his alleged criminal activities were confirmed, Ukraine would act appropriately.
Poroshenko gave Saakashvili Ukrainian citizenship in May 2015, when appointing him as the governor of Odesa.
Saakashvili's party, 'Movement of New Forces, ' (MNF) said if correct, the withdrawal showed that Poroshenko had chosen "a path of anti-constitutional acts for the sake of the usurpation and retention of power at all costs".
Saakashvili, 49, is an adamantly pro-Western reformist who was swept to power in Georgia by the peaceful Rose Revolution protests of 2003 and served two terms as president in 2004-2013.
Afghan officials calls Taliban claims regarding Hebatullah's son a 'propaganda'
Taliban have in the past exaggerated their successes and the remoteness of the area made it impossible to independently verify. The US air strikes are part of a North Atlantic Treaty Organisation mission to support Afghan forces against the Taliban.
On July 25 Saakashvili wrote on Facebook that he was in the United States.
Although Poroshenko gave no explanation for the decision, Leshchenko said it was created to force Saakashvili "to take an asylum in America and forget about Ukrainian politics".
The immigration service stated that Saakashvili's case, including the newly obtained documents, had been sent to the citizenship commission. Receiving Ukrainian citizenship meant Saakashvilis Georgian citizenship was automatically revoked, as Georgian legislation prohibited people from holding dual citizenship except for in exceptional circumstances. At the time Saakashvili was in exile from Georgia and faced abuse of office charges if he returned.
Georgias Chief Prosecutor Irakli Shotadze says that Ukraines Constitution is a key obstacle for former President Mikheil Saakashvilis extradition to Georgia.
"Every day that I have had a Ukrainian.passport I have worked so that Ukraine could win and become a real European country", he said.
Throughout his political career, Saakashivili, who studied to become a lawyer in America, has been positioning himself as a strong USA ally. "I am more Ukrainian than the majority of today's [Ukrainian] lawmakers".
- Wonder Woman Will Be Back to Save America in December 2019
- California girl arrested after livestreaming deadly auto crash
- Nifty ends above 9900, Reliance Industries leads
- Massive CA Wildfire Threatens Power to Yosemite
- Forget The Crown Vic: Ford Launches F-150 Police Responder
- Eight killed, 30 injured in Lahore blast
- North Korea could launch reliable nuclear-capable missile by 2018
- Elon Musk Gets 'Approval' for NY to DC Hyperloop
- Virat Kohli expresses wish ahead of first Test against Sri Lanka
- Tapper Goes After Scaramucci For Changing His Stance On Trump