Many believe the police operation is the fallout of a deepening rift between Erdogan's government and a powerful U.S.-based moderate Islamic cleric, Fethullah Gulen, whose followers are reported to have a strong foothold within Turkey's police and judiciary.
Police searching the home of Halk Bank's CEO, Suleyman Aslan, discovered the shoeboxes containing money on his bookshelves, the Dogan news agency reported. It said Aslan's wife, who was also detained, was heard in a wiretapped telephone conversation as saying "the greens have arrived,' allegedly in reference to dollar bills. Arinc said Aslan's wife was released late Tuesday and no longer was in police custody.
Dogan, a reliable news source, cited unidentified judicial officials for its report. A national police official said he could not immediately confirm the report, while officials at the Interior Ministry refused comment. Arinc said he had no information on the money that had reportedly been seized. Halk Bank said police had requested information concerning their investigation but had no other comment on the case.
Analysts say the investigation is the latest round of a power struggle between Gulen and Erdogan's government. The cleric's movement long supported Erdogan's Islamic-based Justice and Development Party but has fallen out with the Turkish leader over his plans to close down private cram schools that are a major source of income for his group.
Arinc, the deputy prime minister, defended the government's record in fighting corruption and promised it would not impede the investigation.
"We believe that our friends are innocent," Arinc said. "This does not mean, however, that they will be protected if they have been involved in criminal activity."
Still, in a sign that Erdogan was fighting back against the probe, five senior police officials were removed from duty Wednesday. Turkish media reports said they included commissioners in charge of combatting organized crime, smuggling and criminal financial activity and oversaw the corruption detentions.
Erdogan has suggested that the probe is a politically motivated "dirty trap" to harm his government. The investigation comes before local elections in March that are largely seen as a vote of confidence in Erdogan's government.
Erdogan himself is expected to be a candidate in the presidential election in August.
"There is a dirty operation taking place," Erdogan said Wednesday during a joint news conference with the visiting Hungarian prime minister. "While we are striving to make Turkey one of the world's top 10 nations by 2023, others are engaged in thwarting Turkey's rapid rise."
Turkey's financial markets have been turbulent since Tuesday's raids, with the markets sliding and the Turkish Lira drifting downward against the dollar.
Police confirmed to The Associated Press that the sons of three government ministers have been held for questioning: Economy Minister Zafer Caglayan, Interior Minister Muammer Guler and Environment and Urban Planning Minister Erdogan Bayraktar.
Opposition parties have demanded that the three ministers resign and criticized the dismissal of the five police chiefs, calling it an attempt to cover up the scandal.
Arinc didn't say whether the ministers planned to resign or would be removed from their government positions.
"You will soon see what will happen," he told reporters.