TUNIS (Reuters) - Tunisian politicians tried to form a unity government on Sunday but the relative calm enforced by the army two days after the president was ousted was broken by a gunfight outside an opposition party headquarters. Prime Minister Mohamed Ghannouchi said on state television that the creation of a new government will be announced in Tunisia on Monday. Tomorrow we will announce the new government which will open a new page in the history of Tunisia, Ghannouchi said in a brief statement. Meanwhile, Tunisian military special forces exchanged fire with members of the ousted presidents security force Sunday evening near the presidential palace in a Tunis suburb, a military source told Reuters. Two witnesses who live near the palace, in the Carthage area several kilometres (miles) from the centre of Tunis, said they could hear heavy and continuous gunfire. The PDP party said police and military stopped a carload of armed men and shots were fired. Police said two of the suspects they caught after chasing them into apartment buildings had Swedish passports. They also arrested a Tunisian. During the day, tanks were stationed around Tunis and soldiers were guarding public buildings after drive-by shootings and jailbreaks on Saturday in which scores of inmates were killed in the chaos. Residents, some of whom had said they were starting to get back to normal life during daylight hours, were rebuilding makeshift barricades from branches and trash cans to block their streets and protect property as the night curfew approached. We came out on the streets and dressed in white vests so we can identify one another. We told the police in the neighborhood that we are here and were dressed in white - it was during curfew hours ... some brought sticks and we collected rocks, one man told Reuters Television earlier in the day. The official who was in charge of security for ousted President Zine al-Abidine Ben Ali is to appear in court on charges of stoking violence and threatening national security. Al Jazeera television said a replacement had been appointed. Analysts say there may be more protests if the opposition believes it is not sufficiently represented in a new government. Sunday was not a working day and the streets were quiet, but some people were shopping for food. For the first time in days, a few vans and pick-up trucks were making deliveries. On the highway heading north into Tunis, a group of youths with sticks and knives were stopping private cars and robbing them just a few kilometers from an army checkpoint, a Reuters Television crew said. Showing their contempt for Ben Alis family, several hundred people filed through the empty, ransacked home of the former presidents nephew, Kaif Ben Ali, taking photographs, picking up plants as souvenirs and stripping out plumbing fixtures. The villa is in the chic Mediterranean resort of Hammamet, about 60 km (40 miles) from the capital, where many of the moneyed elite close to the ousted president had their homes. The speaker of parliament Fouad Mebazza, sworn in as interim president, has asked Prime Minister Mohamed Ghannouchi to form a government of national unity and constitutional authorities said a presidential election should be held within 60 days. Ghannouchi was holding more talks on Sunday to try to fill the vacuum left when Ben Ali, president for more than 23 years, fled to Saudi Arabia following a month of protests over poverty, jobs and repression that claimed scores of lives. While there have been relatively positive noises from the talks so far, the negotiations may run into trouble when they get down to the detail of which parties get which cabinet post and how many of the old guard are included. Ahmed Ibrahim, head of the opposition Ettajdid party, said he and other party leaders would meet Ghannouchi. The main thing for us right now is to stop all this disorder. We are in agreement on several principles concerning the new government. We will continue to discuss. My message is to say no to Gaddafi: we do not want to go backwards, he said, in reference to a speech by Libyan leader Muammar Gaddafi who said Tunisians were too hasty to get rid of Ben Ali. Opposition parties want assurances that presidential elections will be free, that they will have enough time to campaign, that the country will move toward greater democracy and that the power of the ruling RCD party will be loosened. Two opposition parties have also already said the two-month deadline for holding elections is too soon. Opposition leader Najib Chebbi said after talks with Ghannouchi on Saturday that elections could be held under international supervision within six or seven months. Beirut-based commentator Rami Khouri said it could take a while for Tunisias opposition of secularists, leftists and Islamists to coalesce because there was no unified movement. The process will probably take weeks at least and then you have to sort out the logistics of the interim government, the unity cabinet ... you have never had an Arab country where the people can suddenly start from scratch, he told Reuters. The ousting of Tunisias president after widespread protests could embolden Arab opposition movements and citizens to challenge entrenched governments across the Middle East. It was always said that the Arab world was boiling but the continued state of stagnation made some doubt infiltrate minds. I think this doubt has now gone, Hany al-Masri, a Palestinian commentator based in Ramallah, said. Hamas supporters rallied in Gaza holding large posters of Ben Ali bearing the words: Oh, Arab leaders, learn the lesson. The army was drafted in last weekend to reinforce the police. Since then, they have maintained a strong presence on the streets, backed by military helicopters. The people may be offered the appearance of freedom minus the dictator, followed by a new clampdown on Tunisian political life, Islamic scholar Tariq Ramadan said on his website. A military source said people still loyal to Ben Ali were behind the drive-by shootings in Tunis on Saturday. Western and Arab powers have called for calm and unity. The French government called on Tunisia to hold free elections as soon as possible and said it had taken steps to ensure suspicious financial movements concerning Tunisian assets in France are blocked administratively. Hundreds of European tourists stranded by the unrest have been flown home on emergency flights. A French photographer died after sustaining head injuries on Friday from a tear gas canister fired by a police officer, Reporters Without Borders said.