Five members of Algeria's security forces have been killed in three separate attacks just days before a national referendum.
The conflict with Islamists has taken a huge toll
Media reports blamed the violence on Islamic militants.
On Thursday, Algerians vote on a plan to grant a partial amnesty to Islamist rebels and government forces involved in the civil war.
Violence has fallen sharply in recent years after over a decade of violence sparked by a cancelled election.
Two security guards were killed in an ambush in the mountainous area of Ain Defla, south-west of the capital, Algiers.
Unidentified gunmen in the western province of Saida killed two military policemen.
And one soldier died when a roadside bomb exploded as a military convoy was passing near the eastern town of Boumerdes.
The Algerian president has called a referendum on national reconciliation due to take place on 29 September.
He urged people to go to the polls and voice their opinion on a proposed partial amnesty for Islamic extremists.
Those guilty of massacres, terror attacks or rapes would be excluded from the amnesty, he said.
Militant Algerian groups have killed some 150,000 people since 1992, when elections in which an Islamic party was poised to win were cancelled.
President Abdelaziz Bouteflika said the referendum was aimed at "definitively turning the page on the political crisis" sparked by the insurgents' struggle.
He vowed the vote would be "transparent, democratic and fair".
The proposed amnesty entails dropping charges against rebels who gave up arms after 13 January 2000, when legislation on civil reconciliation took effect.
It was initially expected to apply to all insurgents, but a re-think of the plan was prompted by the Salafist Group for Preaching and Combat, which praised the murder of two Algerian diplomats in Iraq last month.
The reconciliation charter, due to be voted on in the referendum, also envisages re-establishing the rights of Islamists who lost their jobs in the 1990s crackdown.
But the president made it clear that whoever fomented "the policy of pseudo-jihad against the nation and its institutions" would be banned from entering politics.
The families of those killed in the clashes will be entitled to compensation, he said.
Mr Bouteflika first launched his controversial reconciliation initiative at the start of his first term as president in 1999.
Violence has not ceased completely since, but the number of attacks has gone down in recent years.