BAGHDAD, Oct. 2 (Xinhua) -- Up to 13 people were killed and 25 wounded Wednesday in Iraq's violence, including the downing of a military helicopter, police said.
In the early hours, Iraqi security forces backed by two helicopters carried out an operation on an insurgent stronghold north of Tikrit, the capital of Salahudin province about 170 km north of Baghdad, a provincial police source told Xinhua.
One of the helicopters was shot down by militant fire while taking off after dropping commandos onto the battlefield, all its four crew members killed, the source said.
At least three militants were killed in the fierce clashes, the source added.
Later in the day, the other helicopter was hit by ground fire but managed to make an emergency landing in a military base, and no casualties were caused, the source added.
In a separate incident, Mahmoud Khalaf, the mayor of the city of Samarra, some 110 km north of Baghdad, escaped unharmed a roadside bomb explosion near his convoy, but a girl was killed and one of his bodyguards was wounded, the source said.
Also in Salahudin, a lawyer was killed by a bomb attached to his car in the city of Shirqat, some 280 km north of Baghdad, a local police source said.
Elsewhere, a civilian was killed and 15 wounded in a car bomb explosion near the local government office of Kirkuk city, some 250 km north of Baghdad, a local police source told Xinhua.
The blast also destroyed 19 civilian cars nearby and caused damaged to several buildings, the source said.
West of Baghdad, gunmen using assault rifles attacked the convoy of Lieutenant Colonel Ayub al-Kurdi on a main road, killing one of his bodyguards and wounding him and two other bodyguards, a local police source told Xinhua.
In northern Iraq, a car bomb went off near a police patrol in the town of Tal Afar, some 70 km west of the city of Mosul, which is about 400 km north of Baghdad, killing a policeman and wounding three others, a local police source said.
In Iraq's eastern province of Diyala, gunmen shot dead a Sunni district official and wounded his relative north of the provincial capital of Baquba, about 65 km northeast of Baghdad, a provincial police source told Xinhua.
Also in the province, two policemen were wounded in a roadside bomb explosion near a government-backed tribal council in the city of Maqdadiyah, some 40 km northeast of Baquba, the source said.
Iraq is witnessing its worst eruption of violence in recent years, which raises fears that the country is sliding back to the full-blown civil conflict that peaked in 2006 and 2007, when monthly death toll sometimes exceeded 3,000.
The UN Assistance Mission for Iraq has said that almost 6,000 civilians were killed and over 14,000 others injured in Iraq from January to September this year.