Cyprus’ authorities and banks are cooperating with the US in investigation into the activities of Paul Manafort, the former head of President Donald Trump’s election campaign, the government spokesman said on Monday.

“The particular case, as I have heard without being particularly familiar with it, concerns some disputed or illegal act carried out by someone,” spokesman Prodromos Prodromou said.

“Vigilance is always needed and I have to say that Cypriot authorities are in complete cooperation with US authorities which are carrying out certain investigations and with authorities of other countries,” Prodromou said in an interview to state television channel CyBC on Monday. “US authorities are cooperating with Cypriot banks.”

Manafort is a target of special counsel Robert Mueller who is investigating a probable collusion of the Trump campaign with Russia. In October, Mueller charged Manafort, who is linked to a number of companies in Cyprus, on various counts including money laundering, tax evasion and acting as an unregistered foreign agent before filing additional charges in February.

Manafort, an advisor of Ukraine’s former president Viktor Yanukovych, denies any wrongdoing. Four months ago, Mueller also charged him with lying to banks to secure loans. Manafort is now facing additional indictments after Mueller accused him and his Russian aide Konstantin Kilimnik of attempting to tamper with witnesses. Kilimnik is attributed with ties to Russian spy agencies, an allegation which he also denies.

Prodromou said that Cyprus – which in March 2013 discovered that other euro area member states were unwilling to bail out its undercapitalised banks on the grounds that they allowed Russian oligarchs to launder money – “was once on the grey list of the OECD (Organisation for Economic Cooperation and Development) but now is rehabilitated”.

“In recent years, all those measures and safety valves have been adopted so that there is security and control in financial transactions,” he said.

“All controls are carried out that need to be carried out,” the government spokesman said. “(And) where improvements have to be made, we are in cooperation not only with US authorities but also other countries. We are in the era of the automatic exchange of information between jurisdictions.”

A month ago, it emerged that Marshall Billingslea, the assistant head of the US Treasury in charge of terrorist financing, received assurances from Cypriot authorities that they would do more to prevent illicit actors from using the Cypriot banking system and would cooperate with the US in combating corruption, money laundering and other financial threats.

Bank of Cyprus has repeatedly said in the past that it had terminated all remaining accounts belonging to Manafort or entities linked to him by 2014, a year after the bank took over the operations of Cyprus Popular Bank, widely known as Laiki, and a year before Trump had announced his candidacy.