Pyotr Poroshenko
Ukraine's ex-president Pyotr Poroshenko
The Office of the Ukrainian Prosecutor General has launched an investigation into high treason and abuse of office by ex-president Pyotr Poroshenko after purported records of his conversations with former US vice president and secretary of state were made public, the Ukrayinska Pravda newspaper said.

"The Office of the Ukrainian Prosecutor General made an entry in the unified register of prejudicial inquiry," the paper said, citing sources in the prosecutor general's office.

According to sources, the investigation was launched in line with the Ukrainian Criminal Code's articles on state treason and abuse of power or office.

On Tuesday, Ukrainian lawmaker Andrei Derkach published audio records of phone calls, in which, according to his words, Poroshenko discusses matters of Ukraine's domestic policy with then US Vice President Joe Biden and Secretary of State John Kerry. The lawmaker said that the conversations took place in late 2015 and early 2016.

During one of the conversations between Poroshenko and Kerry, which allegedly took place on December 3, 2015, the US diplomat tells the US president to consider solving the problem of replacing Prosecutor General Viktor Shokin. Kerry also says that Vice President Biden is concerned by the issue.

The records also contain other information that indicates US interference in Ukraine's domestic affairs. Among other things, Biden tells Poroshenko to nationalize Ukraine's largest commercial lender PrivatBank until US President Donald Trump takes office. Poroshenko also reports to US officials about raising tariffs for Ukrainians and reforming state enterprises.