CAIRO (REUTERS) - The Egyptian government has threatened to cancel the licence of an independent TV channel for hosting a popular satirist who was questioned by prosecutors over accusations that he insulted President Mohamed Mursi, state media said on Tuesday.

Bassem Youssef, who rose to fame with a satirical online show after the uprising that swept the previous president Hosni Mubarak from power in 2011, turned himself in on Sunday after the prosecutor-general issued a warrant for his arrest.

The prosecutor accused Youssef, whose programme is shown on the CBC channel and has been compared to US satirist Jon Stewart's "The Daily Show" of insulting Islam and undermining Mr Mursi's standing. He was released on bail on Sunday.

Critics see the case as sign of a crackdown on dissent in post-Mubarak Egypt, charges strongly denied by the government.

Egypt's state investment authority said it had issued a warning to CBC because Youssef's show violated the rules governing the media city in Cairo where the channel and several other stations are located, the state news agency MENA said.

"The show contains vulgarism, insults, sexual gestures and bad language," MENA quoted the investment authority as saying.

"The state body for investment and free zones has sent a warning to CBC that it would lose its licence unless it complied with the rules of the media area," MENA said.

The agency quoted CBC's management as saying that the channel was seeking to comply with the law and ethical standards.

A statement from the presidency rejected criticism that the case represented a clampdown on the media and said the general prosecutor and the country's judiciary were independent.

"Egypt has become since the revolution ... a state of law where the judiciary enjoys independence," the statement said, adding that Egypt also enjoyed press freedom.

The statement came after the United States, opposition officials and rights activists condemned Youssef's questioning.

On Monday, the United States, which gives US$1.3 billion (S$1.6 billion) in military per year to the North African country, accused Egypt of muzzling freedom of speech.

US State Department spokesman Victoria Nuland also suggested that Egyptian authorities were selectively prosecuting those accused of insulting the government while ignoring or playing down attacks on anti-government demonstrators.

Egypt has been in a state of political turmoil since the ouster of Mr Mubarak, a long-time US ally. The political uncertainty and growing street crime has deterred tourism, a key driver of the Egyptian economy.