Turkish Prime Minister Recep Tayyip Erdogan on Friday hit back at critics who wrote an open letter published in British daily The Times blasting his handling of the civil unrest which engulfed Turkey last month.

"Treating our government as 'dictatorial' only shows impertinence...," Erdogan told reporters in Istanbul, referring to the letter.

He blasted the celebrities including Hollywood stars who signed the letter as "insolent".

The Turkish leader added that his government would look into taking legal action against The Times, which he accused of "lacking ethics" willing "to rent its pages for money".

The London newspaper had on Thursday published a full-page open letter addressed to Erdogan, signed by 30 people including Turkish pianist Fazil Say, U.S. film stars Sean Penn and Susan Sarandon, film director David Lynch and British historian David Starkey.

They condemned the brutal police crackdown on anti-government protesters in June that left at least five people dead and some 8,000 injured.

The letter even went as far as to compare the giant pro-government rallies, organized by Erdogan's Islamist-rooted AKP party to counter the protests, to the massive rallies held during Adolf Hitler's Nazi Germany. It branded Erdogan's rule as "dictatorial".

The wave of unrest in Turkey was sparked by protests against controversial plans to redevelop Istanbul's Gezi Park which met with a heavy-handed response by authorities.

Demonstrations erupted nationwide against the government and Erdogan, who many protesters accused of turning authoritarian and seeking to "Islamize" Turkish society

According to police estimates, some 2.5 million people took to the streets in nearly 80 cities for three weeks to demand his resignation.