At least 28 people have been killed and some 60 injured in a car bomb attack on an Algerian naval barracks in Dellys, 100km (60 miles) east of Algiers.
No-one has admitted carrying out the attack in Dellys
The victims were coast guard officials, hospital officials said. They warned the number of the dead could rise.
It comes just two days after a suicide bomber killed at least 19 people in Batna in a crowd awaiting a visit by President Abdelaziz Bouteflika.
After the latest attack, Mr Bouteflika insisted terrorism was "in retreat".
Speaking on Algerian television, he said that by attacking innocent people the attackers had betrayed "their people, their country, their religion".
Terrorism was in decline, he said, "despite the distressing and hurtful consequences of these operations that have targeted the Algerian people".
No-one has admitted carrying out either of the attacks, but the BBC's North Africa correspondent, Richard Hamilton says the finger of suspicion points towards an organisation called al-Qaeda in the Islamic Maghreb.
It was previously known as the Salafist Group for Preaching and Combat (GSPC) but changed its name when it joined forces with al-Qaeda last year.
The group said it was behind a double bombing in Algiers in April which killed 23 people.
Soon after the Batna incident, Mr Bouteflika said Islamic militants were behind that attack.
He denounced them as "criminals", trying to disrupt his policy of national reconciliation, which is aimed at ending 15 years of fighting between the army and groups trying to set up an Islamic state.
"Terrorist acts have absolutely nothing in common with the noble values of Islam," the official APS news agency quoted the president as saying.
The vast majority of Algerians distance themselves from the extremists and after decades of war say they are tired of bloodshed, our correspondent says.