Turkey's Prime Minister Recep Tayyip Erdogan has indicated he may seek the extradition of Fethullah Gulen, the U.S.-based cleric who leads a movement the Turkish government says has formed a 'parallel state' to target Erdogan and his government.

During a televised program on Thursday, Erdogan was asked about a phone call a fortnight ago with U.S. President Barack Obama on Gulen.

Erdogan said he told Obama to act in regard to the activities of the preacher, whom Erdogan called "the source of unrest in my country."

"Obama said he understood the message," Erdogan said.

Erdogan also responded to a question about whether he would seek a red notice - similar to an international arrest warrant - for Gulen, by asking: "Why not?"

"But first you have to lay the groundwork," he said.

The issuing of an international red notice requires Turkey's judiciary to establish that Gulen's actions were criminal.

- Tens of thousands "wiretapped"

Turkey's government says the 'parallel state' wanted to deal a political blow to Erdogan before the local elections on March 30 under the pretense of the anti-graft operation which began on December 17.

Since then, Turkey has witnessed a flurry of wiretapping leaks online, which were related to both the government and Gulen's movement.

Both Erdogan and Gulen have dismissed some of the recordings as doctored, stressing the illegal nature of part of the wiretapping activity that was revealed through the leaks.

Prime Minister Erdogan said tens of thousands of people have been wiretapped as part of an illegal practice he said began in 1980s but reached its peak in recent years.

Several Turkish dailies published documents late last month which showed that prosecutors - allegedly linked to the 'parallel state' - ordered eavesdropping that targeted over 7,000 people in politics, business, civil society, media and academia over a period of three years.

During the program, a journalist asked Erdogan: "How will you confront this plot ('parallel state's activities)? What sanctions will be enforced?"

The Prime Minister responded by saying the judiciary was "designed" to provide impunity to members of the 'parallel state'.

"That's why we began with the HSYK," Erdogan said, referring to a recent judicial reform that changed the organizational structure of Turkey's top judicial body, the Supreme Board of Judges and Prosecutors (HSYK).

Erdogan added his government would seek to do more to fight the 'parallel state' following the local elections. He hinted at the possibility of taking measures on social media and video-sharing websites, where phone-hacking leaks are disseminated.

A recent law that gives a state body tighter control over access to online content has faced criticism in Turkey and internationally. The government says the law will make Internet safer to use.