Egyptian President Mohammed Morsi has rejected calls for early presidential elections as attackers torched the Cairo campaign headquarters of a youth group petitioning for his removal from office.
The developments on Friday come as tensions rise ahead of June 30, when Morsi marks one year in power as Egypt's first freely elected president following the 2011 uprising that toppled autocrat Hosni Mubarak.
Morsi told the state-run Al-Ahram daily ahead of the anniversary that demands for an early presidential vote were absurd and illegal.
He warned against violence during upcoming demonstrations, which the opposition plans for the anniversary to demand his ouster.
"Violating the law, the use of violence or inciting for it are unacceptable and will not be permitted," Morsi told the newspaper on Friday.
"We are in a country with a constitution and law. We had free and fair elections and the talk about early presidential elections is absurd and illegal."
The lengthy interview was a throwback to Mubarak's era when the paper served as a government mouthpiece, glorifying the regime's perceived successes and never challenging authorities.
Unidentified assailants petrol-bombed the opposition campaign's central Cairo offices of Tamarrod, at dawn on Friday causing fire damage to the main entrance but no casualties, the official MENA news agency reported.
The youth volunteer group said it had so far collected seven million signatures for Morsi's removal from office by June 30 and it aimed for 15 million signatures - two million more than the number of votes the embattled president garnered in last year's election, which he won with 52 percent of the votes.
Hassan Shahine, one of the campaign founders, said they had received threats before the 3.30am attack, alerting some activists to stay overnight at the office.
"We were awakened by someone trying to break the door and the glass and then we saw fire under the door, coming at us," Shahine said.
Shahine, who suffered light burns trying to extinguish the fire, blamed Morsi's Muslim Brotherhood for the attack.
The volunteers filed a police complaint against Brotherhood leaders after the attack.
Brotherhood denies attack
A Brotherhood spokesman, Mourad Aly, dismissed the accusations, and said that it had no reason to "burn the office of a group as weak as this".
The youth campaign drive is helping galvanise an opposition that has long been in disarray and demoralised.
It has provoked a counter-drive, called "Tajarod" or "Impartiality," which has gathered millions of signatures in Morsi's support.
At the Cairo offices of the anti-Morsi petition, the front door and the ceiling were blackened from the fire and ashes covered the floor Friday but the group pledged to press on with its campaign.
"We are holding on to our pacifism, we are a peaceful campaign," said activist Mai Wahba, adding that the attack "will only strengthen the opposition."
The petition has no legal force, which underscores the campaign's limitations but the opposition highly depends on the size of the upcoming anniversary protests to give weight to their call.
The organisers said once they had 15 million signatures, they would take the petition to the Supreme Constitutional Court to seek new elections, although there was no basis for this under the country's newly adopted constitution. Morsi has three more years to his term.