Ukraine launches probe into alleged surveillance of ex US envoy

Ukraine said Thursday it had launched a probe into alleged illegal surveillance of former US ambassador Marie Yovanovitch, who is now a key figure in US President Donald Trump's impeachment inquiry.

Trump has denied accusations that he pressured Ukrainian officials to investigate political rival Joe Biden, part of the impeachment inquiry that threatens the US leader with removal from office.

Ukraine said it decided to act after fresh documents were released by US Democrats on Tuesday detailing the controversial removal of Yovanovitch, who served as the US ambassador to Ukraine for nearly three years before she was abruptly called back to the United States in May.

The newly-acquired files showed Trump's personal lawyer Rudy Giuliani working with Ukrainian-born American Lev Parnas last year to pressure Kiev to investigate Biden.

They also showed the two, working with Ukrainian officials, trying to force out Yovanovitch, who was eventually removed by Trump.

The Ukrainian interior ministry said on Thursday it could not ignore "illegal activities" on its territory.

"Ukraine's position is not to interfere in the domestic affairs of the United States of America," the ministry said in a statement.

"However, the published references cited by the Washington Post contain a possible violation of the law of Ukraine and the Vienna Convention on Diplomatic Relations, which protects the rights of a diplomat on the territory of the foreign country," it said.

"Our goal is to investigate whether there actually was a violation of Ukrainian and international law," the ministry added.

"Or whether it is just a bravado and fake information in the informal conversation between two US citizens," it added in the English-language statement.

In November, the 33-year diplomatic veteran during her testimony to Congress said she was subjected to a smear campaign orchestrated in part by Giuliani.