TEHRAN: Iran's main opposition leader Mir Hossein Mousavi vowed more anti-government protests as the authorities announced several arrests Monday over a reported insult to Islamic revolution founder Ayatollah Khomeini.

Mousavi's defiant call came a day after Iran's supreme leader Ayatollah Ali Khamenei issued a stern warning to opposition leaders and accused some of them of battling the Islamic regime. "People have a right to question, they should not be confronted violently," Mousavi was quoted as saying by Rahesabz.net, one of three main websites that report on the opposition. "From now on all protests and demands should be pursued peacefully and lawfully. Nobody among us should make a pretext for those who are against people," he said. Protests triggered by President Mahmoud Ahmadinejad's disputed re-election have been staged sporadically for the past six months, with the latest held on December 7 during which a poster of late revolutionary leader Ayatollah Ruhollah Khomeini was allegedly torn up. Mousavi has faced mounting pressure since the December 7 Student Day protests, when clashes erupted on many campuses across Iran, and the sloganeering also has grown more radical than in the early protests. Khamenei on Sunday called on opposition leaders to distance themselves from protesters after thousands of regime loyalists held angry demonstrations against the "insulting" of Khomeini. The authorities also vowed to prosecute offenders and several people have been arrested over reported insults targeting Khomeini and his successor Khamenei in anti-government protests, the prosecutor general said on Monday. "One culprit was arrested on that day. He is in jail and the case is due to be sent to court soon," Abbas Jafari Dolatabadi was quoted as saying by the ILNA and Mehr news agencies. Asked if anyone had been arrested for insulting Khamenei, he said that "those arrested are from both groups," without elaborating. "We are sure about some of them -- their offence is proven and they have confessed," he added. Mousavi, who was Khomeini's protege and Iran's premier during the 1980-1988 war with Iraq, has condemned the controversial act but he also held hardliners responsible for provoking it. "If people's questions were answered and they were not confronted violently we would not see some controversial moves today," he was quoted as saying on Monday. "People want an end of the security-obsessed atmosphere as in such an atmosphere radicalism grows." The opposition charging that Ahmadinejad's re-election in June was fraudulent has seen scores of its prominent figures and supporters arrested in the aftermath of the poll. About 4,000 people were initially arrested and about 140 were put on trial. Among them several top reformist politicians have been sentenced to several years in jail over their alleged role in instigating the protests. Mousavi and other opposition leaders have denounced the "show trials" and sought justice for the dozens killed in the protests. More than 200 people were also arrested on December 7 and the authorities have vowed that they will not tolerate further protests, which have plunged the Islamic republic into the worst political crisis since its formation in 1979.