Vatican police raided the offices of the Holy See's Secretariat of State and its Financial Information Authority, or AIF, on Tuesday and took away documents and electronic devices as part of an investigation of suspected financial irregularities, a Vatican statement said.
It was believed to be the first time the two departments were searched for evidence involving alleged financial crimes.
The Secretariat of State, the most powerful department in the Vatican, is the nerve center of its bureaucracy and diplomacy and the administrative heart of the worldwide Catholic Church.
The AIF, headed by Swiss lawyer Rene Bruelhart, is the financial controller, with authority over all Vatican departments.
The Vatican statement gave no details except to say that the operation was a follow-up to complaints filed in the summer by the Vatican bank and the Office of the Auditor General and were related to "financial operations carried out over the course of time."
A senior Vatican source said he believed the operation, which the statement said had been authorized by Vatican prosecutors, had to do with real estate transactions.
Since the election of Pope Francis in 2013, the Vatican has made great strides in cleaning up its often murky financial reputation.
Last year, a former head of the Vatican bank and an Italian lawyer went on trial to face charges of money laundering and embezzlement through real estate deals. It is still in progress.
In May, the AIF said reports of suspicious financial activity in the Vatican reached a six-year low in 2018, continuing a trend officials said showed reforms were in place.
For decades, the bank, officially known as the Institute for Works of Religion, or IOR, was embroiled in numerous financial scandals as Italians with no right to have accounts opened them with the complicity of corrupt insiders.
Hundreds of accounts have been closed at the IOR, whose stated purpose is to manage funds for the Church, Vatican employees, religious institutes or Catholic charities.
In 2017, Italy put the Vatican on its "white list" of states with cooperative financial institutions, ending years of mistrust.
The same year, Moneyval, a monitoring body of the Council of Europe, gave Vatican financial reforms a mostly positive evaluation.