Turkish Prime Minister Recep Tayyip Erdogan threatened on Saturday to expel foreign ambassadors from Turkey, following what he termed “provocative actions” on their part amid an ongoing corruption investigation that has shaken his government

“Some ambassadors are engaged in provocative actions … Do your job,” Erdogan said in televised remarks.

“We don’t have to keep ambassadors in the country who exceed the limits of their duty,” he added.

Erdogan did not name names but the remarks were considered a warning to US Ambassador to Turkey Francis Ricciardone, who, according to pro-Erdogan media outlets, had told EU envoys that Washington had advised the state-run Turkish bank Halkbank to cut ties with Iran.

“We asked Halkbank to cut its links with Iran. They did not listen to us. You are watching the collapse of an empire,” Ricciardone was quoted as telling EU ambassadors, according to remarks carried by AFP based on reports in Aksam, Bugun, Yeni Safak and Star newspapers.

Ricciardone on Saturday denied the media reports as “baseless allegations,” in his Twitter account in the Turkish language. ”Nobody should put US-Turkish relations into jeopardy through baseless allegations,” he said, according to AFP

The head of Halkbank was arrested earlier this week along with the sons of two government ministers in the investigation, bringing the total number of those detained to 24. The private Dogan news agency said the ministers’ sons and other suspects were accused of taking or facilitating bribes. The son of a third minister and a construction magnate were freed from custody pending trial.

Istanbul police said they seized shoeboxes stashed with $4.5 million in cash at the home of the bank chief.

According to Businessweek, “police have said the inquiry targets organized graft, money laundering and gold smuggling.”

The police raids have threatened to rock Erdogan’s 11-year tenure.

Many believe the police operation is the fallout of a deepening rift between Erdogan’s government and a powerful US-based moderate Islamic cleric, Fethullah Gulen, whose followers are reported to have a strong foothold within Turkey’s police and judiciary.

Erdogan said the corruption investigation is a “dirty operation” to unsettle his government and has vowed to go after those who have instigated it. The Turkish PM has also indicated that there was an “international dimension” to the probe.