The consideration by a court in Geneva of a lawsuit on the return of more than $500 million in funds that are alleged to have been illegally withdrawn from Ukraine by former Prime Ministers Pavlo Lazarenko and Yulia Tymoshenko may take a long time, and Ukraine will file additional materials to the lawsuit, Prosecutor General Viktor Pshonka has said.

"An international authoritative legal organization has already filed a lawsuit with a court in Geneva... regarding the return of this money to Ukraine," he said at a briefing in Kyiv on Tuesday.

However, he said that the issue currently concerns two accounts with more than $500 million in them.

"These are currently two accounts, but there is a continuation of all this and there are materials that will be completed and submitted to court for an even larger amount of funds. These funds were at one point illegally transferred to the accounts of a bank in Geneva," he said.

"We have information that these accounts were controlled by Tymoshenko," Pshonka added.

He noted that it is difficult to predict when these funds could be returned to Ukraine, as it is quite a lengthy legal procedure.

"This issue is not resolved in a day, a month and six months," he said.

Pshonka added that there is hope for a positive outcome.

He said that the Cabinet of Ministers had made a decision on the return of illegally transferred funds and instructed the Income and Tax Ministry to deal with the matter.

The Income and Tax Ministry, under the supervision of the Justice Ministry, drafted an agreement with a reputable international organization that was mandated to find the funds and return them to Ukraine.

"The Prosecutor General's Office itself provided documents to the Income and Tax Ministry and this international legal organization, which were included in the case materials," he said.

As reported, in early November 2013, the Income and Tax Ministry of Ukraine started legal proceedings in the United States and in Switzerland to protect the interests of Ukraine in the case of the misappropriation of over $200 million by a group of people, allegedly including two former Ukrainian prime ministers, Yulia Tymoshenko and Pavlo Lazarenko. The ministry instructed the Lawrence Graham LLP law firm (London, Britain) to act as lead counsel in coordinating the country's claims in litigation abroad.

Last week Pshonka visited Switzerland, where he met with the prosecutor general of the Canton of Geneva. Pshonka said that authorized Ukrainian agencies, with the assistance of international legal structures, are actively working to find on doubtful foreign accounts the funds that were illegally removed from Ukraine, and are also taking steps to return them to Ukraine through court rulings.

He said that one of the lawsuits in Ukraine's interests had been filed with a Swiss court.