(CNN) -- Iraqi security forces on Thursday thwarted an attack by an al Qaeda splinter group on a military base in central Iraq, killing 40 gunmen, Iraq's Interior Ministry said.
One Iraqi army officer was killed in the attack by members of the group calling itself the Islamic State of Iraq and Syria, according to the ministry.
The attack happened at a base in Yusufiya, about 40 kilometers (25 miles) south of the country's capital, Baghdad.
Also Thursday, a car bomb exploded outside a restaurant in northern Iraq, killing at least four people and injuring 13 others, police officials in Tikrit and Kirkuk said.
The restaurant was in Tuz Khurmatou, about 200 kilometers north of Baghdad.
Iraq has been beset with political and sectarian violence for months, often pitting Sunnis -- a minority in Iraq -- against Shiite Muslims, who came to dominate the government after Iraqi leader Saddam Hussein was overthrown in 2003.
The United Nations said 2013 was the deadliest year in Iraq since 2008, with almost 8,000 people killed.
In March alone, terrorist attacks and other violence killed 592 people and injured 1,234 others in Iraq, excluding Anbar province, according to the United Nations
The United Nations in March kept separate, civilian-only figures for Anbar, which has seen intense fighting between Sunni extremists and Iraqi security forces since the beginning of this year. More than 480 civilians, including 133 civilian police officers, were killed, and 1,104 civilians were injured last month in Anbar, the United Nations said.
In February, more than 700 people were killed and nearly 1,400 others were wounded in Iraq, according to the United Nations.