The US' federal government watchdog says the White House broke the law in withholding aid to Ukraine, the issue at the heart of the impeachment of President Donald Trump.
He was impeached last month on charges of abusing his power, accused of pressuring Ukraine to investigate political rivals, and then obstructing a probe into the issue.
On Thursday the Government Accountability Office (GAO) said the White House Office of Management and Budget violated the law by holding up the assistance to Ukraine.
In a statement on the GAO website, the general counsel of the GAO, Thomas Armstrong, wrote: “Today, GAO issued a legal decision concluding that the Office of Management and Budget violated the law when it withheld approximately $214 million appropriated to DOD for security assistance to Ukraine.
"The President has narrow, limited authority to withhold appropriations under the Impoundment Control Act of 1974. OMB told GAO that it withheld the funds to ensure that they were not spent “in a manner that could conflict with the President’s foreign policy.”
The law does not permit OMB to withhold funds for policy reasons.”
The revelations came as the U.S. Senate opened the impeachment trial of Trump with a quiet ceremony. Senators swore an oath of "impartial justice" and House prosecutors formally recited the charges against the president.
The trial, only the third such undertaking in American history, is unfolding at the start of the election year, a time of deep political division in the nation.
Four of the senators sitting in judgment on Trump are running for the Democratic Party's nomination to challenge him in the fall.
Senators filled the chamber, an unusual sight in itself, sitting silently under strict rules that prohibit talking or cellphones, for a trial that will test not only Trump's presidency but also the nation's three branches of power and its system of checks and balances.
Ukraine investigates possible illegal surveillance of US ambassador
Meanwhile Ukrainian police today opened a probe into whether the US ambassador came under illegal surveillance before she was recalled from her post in May this year.
This comes two days after Democrats in the US released documents showing an associate of Trump's personal lawyer communicating about the removal of Marie Yovanovitch from her position as ambassador to Ukraine.
Lev Parnas, an associate of Trump's lawyer Rudy Giuliani, has since claimed Trump was directly involved in the effort to pressure Ukraine to investigate Democratic rival Joe Biden.
On Wednesday he said in a televised interview on MSNBC: “President Trump knew exactly what was going on.”
The Soviet-born Florida businessman is facing a raft of criminal charges related to campaign finance violations.
“He was aware of all my movements. I wouldn’t do anything without the consent of Rudy Giuliani, or the President,” he added.
The Ukrainian Interior Ministry, which runs the police forces, said in a statement that Ukrainian police "are not interfering in the internal political affairs of the United States.''
"However, the published messages contain facts of possible violations of Ukrainian law and of the Vienna Convention on diplomatic relations, which protect the rights of diplomats on the territory of another state," the statement continued.
"Our goal is to investigate whether there actually was a violation of Ukrainian and international law, which could be the subject for proper reaction. Or whether it is just bravado and fake information in the informal conversation between two U.S. citizens,'' the ministry said.
The Interior Ministry added it had asked the FBI to provide relevant materials, suggesting the US should take part in the investigation.