Algerian soldiers shot dead three Islamist militants Wednesday, raising to 25 the number of suspects killed in a sweep east of the capital where jihadists operate, the defence ministry said.

The ministry said "three terrorists" armed with automatic weapons were killed.

Twenty-two armed Islamists were killed on Tuesday, the first day of a vast operation in the mountainous Ferkioua area of Bouira province, according to the ministry.

It said automatic weapons, ammunition and other weaponry were seized.

A security source told AFP the army was keeping up the operation "to neutralise other members of the armed group".

The sweep was launched on the back of information of a large group of militants in the area, a zone of operations of Jund el-Khilafa, a local affiliate of the Islamic State jihadist group that beheaded a French tourist in September.

A judicial source said experts were trying to determine if the dead militants were members of Jund al-Khilafa or of Al-Qaeda's North African branch.

Jund al-Khilafa militants kidnapped and beheaded mountain guide Herve Gourdel in September 2013 in Kabylie, east of Algiers, in retaliation for France participating in US-led air strikes against IS in Iraq.

Its leader Abdelmalek Gouri was killed in an army operation last December in Issers, 60 kilometres (35 miles) east of the capital.

The army says it has now killed 59 armed Islamists since the start of this year.

Islamist-linked violence rocked Algeria in the 1990s but has since waned, although armed groups remain active in central and eastern Algeria where they mount attacks on security forces.