Police in Germany have raided the offices of Deutsche Bank in connection with the Panama Papers revelations and as part of an investigation into alleged money laundering.

About 170 police officers, prosecutors and tax inspectors searched six Deutsche Bank offices in and around Frankfurt, the public prosecutor’s office said. Investigators are looking into the activities of two Deutsche Bank employees who allegedly helped clients to set up offshore companies to launder money, it added.

The Panama Papers, published by the Guardian and a consortium of international journalists in April 2016, revealed how offshore tax havens including the British Virgin Islands were used to hide billions of dollars.

The prosecutor’s office said it had seized written and electronic business documents. Police cars were parked outside the headquarters of the bank, Germany’s biggest lender.

In a statement Deutsche Bank said it would “cooperate closely with prosecutors”, adding that it was “anxious to clarify all suspicions”. The bank said it believed it had previously handed over to the authorities all relevant information in the Panama Papers case.

Records from the Panamanian law firm Mossack Fonseca were the basis of the Panama Papers investigation and included more than 10m documents. The revelations caused protests in several countries and led to the resignation of heads of state, including in Iceland and Pakistan.

Deutsche Bank’s Geneva branch held accounts for two offshore companies belonging to the family of Pakistan’s former prime minister Nawaz Sharif. The firms owned four luxury flats in Mayfair, which were at the centre of corruption charges against the Sharifs. In July Pakistan’s anti-graft court sentenced Sharif to 10 years in jail, and his daughter Maryam to seven years. The Sharif family denies wrongdoing and maintains that a Qatari prince gifted the property to Nawaz’s children to repay an old debt. In September Nawaz and Maryam were released pending an appeal.

Anti-corruption groups welcomed the raid in Frankfurt and said it was a “nail in the coffin of the opaque offshore world”.

“Almost three years on, and law enforcement are still relying on the Panama Papers for their work. It shows how investigative journalism has been at the forefront of opening the door on a morass of morally dubious – and sometimes illegal – activity by banks,” Ava Lee, a campaigner at Global Witness, said.

She added: “How much more money needs to be siphoned into tax havens before we say enough is enough?”

Deutsche Bank has been involved in the offshore world for decades. Fourteen German banks used the Panamanian law firm to set up more than 1,200 anonymous shell companies. By 2007 Deutsche Bank is said to have brokered or managed more than 400 of them.

Several banks, including the Swedish lender Nordea, have already been fined by financial regulators for violating money laundering rules as a result of the Panama Papers.

German prosecutors said they were looking at whether Deutsche Bank may have assisted clients to set up “offshore companies” in tax havens so that funds transferred to accounts at Deutsche Bank could skirt anti-money-laundering safeguards. Those allegedly involved were two bank employees – aged 50 and 46 – and others not yet identified.

In 2016 alone, more than 900 customers were served by a Deutsche Bank subsidiary registered on the British Virgin Islands, generating €300m, prosecutors said.

They said Deutsche Bank employees were alleged to have breached their duties by neglecting to report money laundering suspicions about clients and offshore companies involved in tax evasion schemes.

The investigation is separate from another money laundering scandal surrounding the Danish lender Danske Bank, where Deutsche Bank is involved.

Denmark’s state prosecutor filed preliminary charges on Wednesday against Danske for alleged violations of the country’s anti-money-laundering act in relation to its Estonian branch.

Danske is under investigation for suspicious payments totalling €200bn from 2007 onwards and a source with direct knowledge of the case told Reuters that Deutsche Bank helped to process the bulk of the payments.