Story highlights Since last Thursday, 23 inmates have been executed

Authorities have executed dozens of inmates in recent months

The executions have sparked concern from human rights advocates

Iraqi authorities executed six inmates Monday, the nation's Justice Ministry said.

Four of them were convicted of terrorism, and two others were convicted of kidnapping and killings, the ministry said in a statement.

Despite a United Nations call for restraint, Iraqi authorities have executed dozens of inmates in recent months.

Authorities executed 11 prisoners Sunday and six others Thursday after terrorism convictions, officials said. More than 100 people have been put to death since November, according to a CNN tally.

The execution of large groups of prisoners has drawn attention from human rights advocates, who have raised concerns about the fairness of trials and transparency of court proceedings.

"Our main concern is, what were these people actually convicted of?" Joe Stork, deputy Middle East director at Human Rights Watch , told CNN in August. " 'Terrorism' does not tell us very much."

After 34 inmates were executed on one day this year, the United Nations' top human rights official said she was shocked and called on the country to implement a moratorium on the death penalty.

"Even if the most scrupulous fair trial standards were observed, this would be a terrifying number of executions to take place in a single day," U.N. High Commissioner for Human Rights Navi Pillay said at the time.

The executions come as Iraq smolders with sectarian tension and political infighting.

Violence in Iraq surged last month, with 365 deaths reported, the Interior Ministry said Monday. That's the deadliest single month since August 2010, when the toll reached 426, the ministry said.

Insurgent attacks against civilians and security forces persist in the country, though violence has dropped dramatically since the peak of Sunni-Shiite clashes in 2006 and 2007.

Baghdad's Shiite-dominated government has blamed the recent attacks on Sunni insurgents with ties to al Qaeda.