Iraq executed 42 people, including a woman, this week for mass killings and other “terrorism” offenses, the Justice Ministry and the United Nations said Thursday after a surge in sectarian violence.

The U.N. mission in Iraq said it was concerned about the executions, which took place Tuesday and Wednesday, and Amnesty International described the news as “extremely alarming.”

Both urged Baghdad to immediately suspend the death penalty, which rights groups say has been used with increasing frequency by Iraqi authorities in recent years.

Sixty-eight death sentences were carried out in 2011, according to Amnesty.

The 42 hanged this week amounted to almost a third of the total number Amnesty said were put to death in all of 2012, when Iraq ranked third in a list of countries that carried out the most executions, behind China and Iran.

More than 6,000 people have been killed in attacks across Iraq this year, as a Sunni Islamist insurgency that includes attacks by al-Qaeda’s Iraq branch gains momentum.

After the 2003 invasion of Iraq, the U.S.-led interim authority suspended the death penalty, citing its use as a tool of repression under dictator Saddam Hussein, who left behind mass graves filled with thousands of bodies.

But as sectarian carnage began to take hold of the country in 2005, Iraq reinstated the punishment for those who commit “terrorist acts,” as well as people who provoke, plan, finance and enable others to perpetrate them.