The United Nations has suspended its mine-clearing operations in southern Afghanistan after a roadside bomb killed two deminers and injured five others.

An Afghan woman passes an old wall painted with different types of mines
The decision to halt demining is the latest setback for the United Nations as it tries to expand its development projects in the restive south of Afghanistan.

The bomb blast this week was the third attack on Afghan deminers in the past two weeks, and brought the death toll to five.

Attacks on aid workers and U.N. staff have increased recently as insurgents expand their campaign against the U.S.-backed central government.

The U.N. Mine Action Center says the violence has forced the suspension of projects in three southern provinces.

U.N. spokeswoman Ariane Quentier told reporters the demining work will only resume when Afghan security officials improve protection for U.N. staff. "I am quoting John Kelly, the program manager at the United Nation's Mine Action Center in Afghanistan, and he is saying, 'We condemn these targeted attacks against deminers and call on the Afghan authorities to bring justice to the perpetrators of these crimes.'"

Mines and unexploded ordinance in Afghanistan kill or wound up to 100 people a month. Nearly half the victims are children.

Most of the landmines were planted during the 1980's by Soviet and pro-Soviet Afghan forces.

The mines restrict access to agricultural land and are a major obstacle to U.N.-backed refugee resettlement programs.

Since March, U.S.-led coalition forces have intensified their campaign against insurgents in southern Afghanistan, killing or capturing more than 200 suspected militants.