KABUL (AP) – Roadside bombs killed four policemen and two Afghan soldiers, and three women died when mortars fired by suspected insurgents hit their homes in an increasingly volatile area just north of the capital Kabul, officials said Tuesday.

Two other policemen were wounded and their vehicle was destroyed in the roadside blast Monday in northern Faryab province’s Ghormach district, the Interior Ministry said.

The Afghan Defense Ministry said two other soldiers were wounded when their vehicle hit a bomb Monday near Qalat city in Zabul province of southeastern Afghanistan.

The ministry said the women in Kapisa province were apparently killed by mortars targeting the district government headquarters Monday night. Earlier that day, U.S. forces fired on a bus carrying civilians outside the southern city of Kandahar, killing four and injuring more than a dozen, and setting off anti-American protests among irate residents.

The entrenched Taliban insurgency is accused of targeting Afghan civilians to spread fear and undercut the authority of Afghanistan’s central government, which remains weak, particularly outside Kabul. Formerly stable areas such as Kapisa have become virtual no-go zones for foreigners and non-governmental organizations.

Civilian deaths remain a source of friction between Afghans and the international forces, although according to U.N. figures, about two-thirds of such fatalities last year were the result of insurgent action. At least 2,412 Afghan civilians were killed in fighting in 2009, an increase of 14 percent from 2008, according to the figures.

Daily life returned to normal Tuesday in Kandahar, the biggest city in the south, where the bus shooting prompted scores of Afghans to block a major highway and chant “Death to America,” while calling for the Afghan government’s downfall.

The attack dealt a fresh blow to U.S. and NATO efforts to win popular support for a coming offensive to drive the Taliban insurgents from what is their spiritual homeland.

Accounts varied about the shooting, with some Afghans saying the bus was fired on as it pulled over to allow a U.S. military convoy to pass. NATO said the bus approached a slow-moving military patrol from the rear at high speed, and troops opened fire after the driver ignored flares and other warnings to slow down.

Also Tuesday, two people were wounded when their tractor ran over a mine in the far southwestern province of Nimroz, the Interior Ministry said.