BAGHDAD, June 18 (Xinhua) -- Iraqi security forces on Wednesday continued fierce clashes with militant groups, while the troops repelled an attack on major oil refinery in Salahudin province, security sources said.
"The security forces backed by the air force repelled an attack by militants on the oil refinery of Baiji, just outside the city of Baiji, some 200 km north of the Iraqi capital of Baghdad, leaving some 40 militants killed," Lieutenant General Qassim Atta, security spokesman of Prime Minister Nuri al-Maliki, said at a news conference in Baghdad.
Earlier in the day, a source from Salahudin provincial police told Xinhua that hundreds of Sunni militants, including the militants linked to the Islamic State in Iraq and Levant (ISIL), an al-Qaida offshoot, who waged an attack at dawn on the refinery compound from several directions with machine guns and mortar rounds.
Fierce clashes between the attackers and the militants and mortar shelling hit a fuel storage and large column of black smoke rose above the area, the source said.
Earlier, insurgent groups overran the city of Baiji as well as large parts the predominantly Sunni province of Salahudin, including its capital Tikrit, some 170 km north of the Iraqi capital.
In Diyala province, the security forces clashed with Sunni militants in several villages near the city of Udheim, some 60 km north of the provincial capital city Baquba, leaving 19 militants killed, Qassim Atta told reporters.
Also in the province, three militants were killed in a clash with a Kurdish security force, known as Peshmerga, near the city of Jalawlaa, in northeast of Baquba, some 65 km northeast of Baghdad, a provincial police source said.
Six Kurdish security members were also wounded by the clash, the source said.
In Anbar province, the troops backed by allied tribesmen have clashed with militant groups in and near the city of al-Qaim, some 330 km northwest of Baghdad, Atta said without giving further details.
Meanwhile, Sunni militants attacked the army bases outside the town of Saqlawiyah, just north of the militant-seized city of Fallujah, some 50 km west of Baghdad, and fought fierce clashes during the day, a provincial police source said without giving details about casualties.
In Iraq's northern province of Nineveh, fierce clashes continued in the city of Tal Afar, some 70 km west of the provincial capital Mosul, for the fourth day, as reinforcement troops have arrived in the city airport by the army helicopters, a security source anonymously told Xinhua.
The troops killed 21 militants and burned four of their vehicles during heavy fighting with militants in al-Saray neighborhood in eastern Tal Afar, the source said, adding that clashes also were underway in several other neighborhoods across the city during the day.
The battles in Tal Afar pushed most of its 250,000 population to flee their homes, mainly to the semi-autonomous region of Kurdistan and the city of Sinjar, some 60 km west of Tal Afar.
Tal Afar itself is the mixed city of mainly Shiite and Sunni Turkomans, in addition to the Kurds and other ethnic and religious minorities.
The Sunni-majority province of Nineveh and its capital Mosul, some 400 km north of Baghdad, have long been a stronghold for insurgent groups, including al-Qaida militants, since the U.S.-led invasion of Iraq in 2003.
The security deterioration in Iraq started on June 10 when bloody clashes broke out between the Iraqi security forces and hundreds of Sunni militants who took control of Mosul and later seized swathes of territories after the Iraqi security forces withdrew from their posts in Nineveh and other predominantly Sunni provinces.