Police have fired tear gas and arrested scores of protesters in Algiers as massive crowds gathered for the first Friday demonstrations since the announcement of presidential elections to succeed deposed leader Abdelaziz Bouteflika.

Police said in a statement on Friday that 108 people were arrested after clashes with “infiltrators” among the protesters, who injured 27 policemen.

Witnesses said police in anti-riot gear fired tear gas in the evening to disperse a crowd of several hundred young people in the city centre after an otherwise largely peaceful demonstration which was joined by families throughout the day.

The crowd size on Friday was estimated at hundreds of thousands of people, although there was no official count. The demonstrators were chanting for the overhaul of the government following Bouteflika’s removal.

Social media has helped drive mass protests which led to the end of Bouteflika’s two-decade rule, have been filled with calls for an eighth consecutive Friday of demonstrations, this time under the slogan of “They will all leave.”

Amel Boubekeur, a research fellow at the School for Advanced Studies in the Social Sciences (EHESS) based in France, told Al Jazeera from Algiers that there was no sign the country’s interim leadership was ready to listen to the demonstrators.

“Since Bouteflika has stepped down, there has been temptation from the regime to repress the demonstrations. The protesters keep gathering in order to say no to repression,” she said.

“Also it doesn’t make sense for demonstrators to reach a solution within the current constitutional framework. They say this constitution is used by the regime to stay in power.”

Dalia Ghanem, a resident scholar at the Carnegie Middle East Center in Beirut, told Al Jazeera that the protesters’ momentum was unstoppable.

“They know what they can achieve with their protests every Friday but also their daily protests. The momentum is here and the status quo is winding up,” she said.

“It seems Algerians are not going to go home until their demands are met. And today their demands are clear. They are asking for the ‘Three Bs’ to leave, meaning [the head of the Constitutional Council, Tayeb] Belaiz, [Prime Minister Noureddine] Bedoui and [interim leader Abdelkader] Bensalah.”

‘Transparent’ polls

Presidential elections are to be held on July 4, Bensalah’s office announced on Wednesday, just hours after he pledged “transparent” polls.

The new date was set a day after Bensalah assumed office for a 90-day period, as stipulated by the constitution but much to the ire of demonstrators.

The appointment of upper house speaker Bensalah as Algeria‘s first new president in 20 years has failed to meet the demands of demonstrators.

Although 77-year-old Bensalah is barred under the constitution from running in the upcoming election, protesters have nonetheless pushed for the close Bouteflika ally to step down.

Students and magistrates have called for renewed rallies and marches in the capital and other cities across the North African country.

For the first time since the anti-Bouteflika protest movement was launched in mid-February, police vehicles and forces tried to block off access to the post office.

But young protesters were undeterred.

“We will be out in large numbers, very large. They don’t know what’s coming. They won’t be able to do anything against us,” said Yassine, 23.

For Mahrez Bouich, a philosophy professor at the University of Bejaia, east of Algiers: “The July 4 election has already been rejected by the people, which also refuses Bensalah’s nomination.”

The demonstrators argue that elections cannot be free and fair if they are held under the same judicial framework and institutions as those of the Bouteflika regime.

Anger is also mounting at military chief, General Ahmed Gaid Salah, who was instrumental in Bouteflika’s departure but then threw his support behind the interim leader, who is seen as part of the old regime.

But the general has stood up for the defence of Algeria’s institutions and warned against the “unrealistic slogans” of protesters aiming to sweep away the whole ruling system.