Former civil-war enemies Renamo and Frelimo have blamed each other for tit-for-tat violence.
Mozambique's president and Renamo are determined to avoid a return to war, a negotiator said this week, after the former rebels declared a 1992 peace deal over.
Two days of tit-for-tat violence have raised fears the country could plunge back into civil war, two decades after the end of one of Africa's bloodiest conflicts in which about a million people were killed.
Members of Renamo, now an opposition party, attacked a police station on Tuesday, hours after the group declared a government raid on its base had broken the peace deal that ended 16 years of fighting.
But in talks with independent negotiator Lourenço do Rosário, Renamo said it reaffirmed that it did not want to return to war.
Instead, it demanded that government forces pull back from the base they seized on Monday, in the central Gorongosa mountains, and it pledged in exchange not to restart hostilities, Do Rosario said.
President Armando Guebuza also renewed his commitment to dialogue as the best way forward despite the skirmishes, according to Do Rosário.
Police fled their post in the central town of Maringue when Renamo fighters opened fire early on Tuesday in an escalation of hostilities between the former rebels and ruling party Frelimo.
"Gunmen attacked the police station, but fortunately there were no casualties because the policemen fled the post," said Maringue's administrator, Antonio Absalao.
Said local teacher Romao Martins: "The situation is horrible. Early this morning, armed men, supposed to be Renamo, attacked, and it was a mess. For one hour, shooting could be heard from all directions and people fled their homes."
Schools have been shut in the region around Renamo's military base in the mountains of central Mozambique.
The town is located about 35km from the base, seized in an operation the ex-rebels said was aimed at killing their leader, Afonso Dhlakama.
But Guebuza said the soldiers had acted in self-defence after Renamo militants fired at them, state news agency Aim reported.
Dhlakama had fled ahead of the attack on the base, according to negotiator Do Rosario, who said both sides acknowledged that there had been no casualties. "He is available to return to the negotiating table already this week," said Do Rosario.
Renamo, the Mozambique National Resistance, which became a political party after the civil war, has not claimed responsibility for Tuesday's attack.
But spokesperson Fernando Mazanga said that Renamo fighters may have been behind it.
"The president of Renamo has lost control of the situation and you cannot blame ... [him] for what happens from here on," Mazanga said.
"The guerrillas are scattered and will attack without taking any orders," he said.
Renamo took up arms against the then communist government of Frelimo, the Mozambique Liberation Front, after independence from Portugal in 1975.
Heading into local government polls next month and a national vote in 2014, Mozambique has a history of election-related violence.
But South African Institute of International Affairs researcher Aditi Lalbahadur said it was "very unlikely that you are going to see a return to war".
Lalbahadur said that Renamo lacked the capacity to engage in a full-scale conflict and that war was not in the interests of the government, though it had more powerful armed forces. "Mozambique is trying to attract foreign investment into the country, so any type of political instability works to their disadvantage," she said.
Renamo, which has faced dwindling political support, is demanding more representation on election bodies and in the armed forces.
The government has said it is open to electoral reform, but accuses Renamo of refusing to budge in negotiations. Over 20 rounds of peace talks have failed.
Tension began escalating last year, after Dhlakama began retraining former guerrilla fighters in the Gorongosa mountains.
The assault on Renamo's base came after the former rebels attacked a government military unit on Thursday, a defence ministry spokesperson said.
Renamo accepted a peace deal after losing its backers, the then Rhodesia and apartheid South Africa, at the end of the Cold War. – AFP