The United Nations said Monday it was scaling back its operations in Kandahar, relocating several foreign employees to Kabul and telling more than 200 Afghan UN workers to stay home.

The announcement came hours after three bombings - one targeting a local police official - shook the city. A recent rash of attacks comes ahead of a joint Afghan-NATO operation to try to wrest control of the area from Taleban militants.

“We are not facing a big threat,” said Ahmad Wali Karzai, a top official in Kandahar province and the most important power broker in southern Afghanistan. He added that the security situation was far worse a few years ago.

“You get one or two incidents once or twice a week,” he told The Associated Press. “That shouldn't be a concern. A suicide attack can happen anywhere.” Since April 12, at least 20 civilians, including eight children, have been killed in Kandahar, according to an AP count. Local officials, aid workers and contractors for US development projects have been targeted by Taleban fighters trying to disrupt the upcoming military operation, expected to accelerate this summer.

A senior Western official familiar with UN operations said 16 UN workers based in Kandahar were moved to a more heavily secured compound Sunday night before going to Kabul and perhaps other destinations. The official spoke anonymously because the information had not been publicly released by the United Nations.

The UN has been on the defensive in Afghanistan since October, when three suicide attackers stormed a Kabul guest house where dozens of staffers lived. Five UN employees and three Afghan citizens were killed in a two-hour siege.

After the attack, the UN sent about 600 of its 1,100 foreign staffers either out of the country or relocated them to safer quarters. Many eventually were recalled to Kabul; others chose not to renew their contracts or terminated their tours in Afghanistan early.

In Kabul, security forces were setting up extra roadblocks and checkpoints ahead of Wednesday's celebration to mark the Mujahedeen victory over the Soviets in the 1980s war.

The deputy police chief in Kabul said a rocket hit the ground near the Ministry of Urban Development in the capital early Tuesday, but there were no casualties.

Violence has marred the celebration in recent years. In April 2008, insurgents tried to assassinate President Karzai during the celebration. Three people were killed and eight others were wounded when militants fired rockets and automatic rifles at Karzai and other dignitaries during a military parade. Two lawmakers were hit by bullets.

The capital has been abuzz with rumors of Taleban plans to attack targets in the city, especially those associated with international organizations. Last week, the Afghan intelligence service announced the arrest of nine militants planning suicide attacks in Kabul.

Five would-be suicide bombers were arrested April 8 at a checkpoint on the outskirts of Kabul along with explosives-laden vests, police said.

Also Tuesday, Afghanistan's interior ministry said a rocket attack killed three civilians and wounded three others inside a home in the northern Kunduz province. The ministry blamed insurgents for the Monday night attack.

Kunduz had been relatively quiet until a few years ago when Taleban activity began to increase, threatening NATO supply routes south from Central Asia.