Violent attacks, mainly targeting security forces, killed 21 people and injured seven across Iraq on Thursday, police said.

In north Iraq, a suicide bomber blew up his explosive-laden car at an army base in a village near the city of Mosul, some 400 km north of the capital Baghdad. A soldier was killed and three others wounded.

Meanwhile, Iraqi security forces foiled an attempt by al-Qaida militants to storm a police base in south Mosul. The troops shot dead a suicide bomber and blew up his car bomb before he could reach his target. They also captured six other militants who were ready to break into the base.

In Iraq's western province of Anbar, a battalion commander and five soldiers were killed in fierce clashes with gunmen in Albu- Bali, east of the provincial capital city Ramadi, about 110 km west of Baghdad. Three gunmen were also killed.

In a separate incident, a suicide bomber rammed his explosive- laden car into an army checkpoint and blew it up on a bridge in the city of Rawa, some 165 km west of Ramadi. The attack killed four soldiers and wounded two others, destroying parts of the bridge.

Anbar province has been the scene of fierce clashes that flared up after Iraqi police dismantled an anti-government protest site outside Ramadi in late December last year.

Separately, a policeman was shot dead near his house in the western part of the city of Tikrit, the capital of Salahudin province.

In the early hours of the day, gunmen broke into the house of a member of the government-backed Sahwa paramilitary group, and killed him and his wife.

In Baghdad, a car bomb was detonated outside the house of a defense ministry officer in Zaiyounah district in east-central part of the capital, causing damages to the house without human casualty.

In Iraq's eastern province of Diyala, gunmen shot dead an owner of a restaurant in the city of Maqdadiyah.

In a separate incident, gunmen shot dead a member of the government-backed Sahwa paramilitary group in the town of Wajihiyah.

Meantime, an intelligence officer was gunned down by armed men when he was driving at a road intersection in northwest Baquba.

Also in the province, a policeman and his wife were wounded when gunmen blew up a bomb in their house in the town of Buhruz.

Iraq is witnessing its worst violence in recent years, as the country is hosting a two-day counter-terrorism international conference. The meeting will tackle various topics, including international cooperation to fight terrorism and media censorship.