ALGIERS (Reuters) - Gunmen ambushed and killed 24 Algerian paramilitary police in the North African oil and gas producer's deadliest insurgent attack in nearly a year, a local newspaper reported on Thursday. Algeria's govt has been fighting the militants allied to the al Qaeda network. Security forces have been able to reduce the level of violence but the insurgents remain a threat. The militants attacked on Wednesday evening using roadside bombs and guns when the paramilitary police passed in a convoy along a highway about 180 km east of the capital, the newspaper Echorouk reported. When they left the scene of the attack they took with them six police off-road vehicles as well as weapons and police uniforms, the newspaper cited security sources as saying. There was no official confirmation of the attack. Two Algerian security sources, who did not want to be identified, told Reuters there had been an ambush and more than 20 paramilitary police had been killed. A death toll of 24 would be the biggest from a single attack since Aug. 19 last year, when 48 people were killed in a bomb attack on a training school for paramilitary police 55 km (34 miles) east of Algiers. Algeria is still emerging from a conflict in the 1990s between the extremists and government forces which killed 200,000 people, according to estimates from international non-governmental organisations. Security crackdowns and a campaign to persuade the militants to lay down their arms have led to a sharp decline in the number of attacks. But a hard core of the militants is still active, now under the banner of al Qaeda in the Islamic Maghreb (AQIM), and the past few weeks have seen an upsurge in violence. Insurgents killed five paramilitary gendarmes late in May and a week later shot dead nine soldiers. At the start of this month, AQIM killed a British man, Edwin Dyer, after holding him hostage in neighbouring Mali. Security experts say the increase in attacks does not mean the group is growing in strength but that it does retain the capability to strike government targets. "Make no mistake: al Qaeda in the Islamic Maghreb is declining," Rachid Ould Bousseafa, the deputy editor of the Echorouk newspaper who writes on security issues, told Reuters. But he said: "Al Qaeda wanted to send a strong message that it is capable of planning and executing a big attack." Though AQIM has not targeted oil and gas infrastructure in Algeria, international energy firms -- which include BP, StatoilHydro, Repsol and Total -- operate under heavy security. Diplomats say the violence also has the potential to spread across the Mediterranean into Europe, where AQIM has a network of undercover cells providing logistical support. The newspaper report said Wednesday's ambush was carried out between the settlements of El Meher and El Mansourah on the N5 highway, a major route linking the capital, Algiers, to cities in the east of Algeria. It said the paramilitary police who came under attack had been assigned to guard a group of Chinese construction workers building a new east-west road link across Algeria. It did not say if any of the workers had been hurt in the attack.