KABUL – Insurgents took aim Sunday at the Afghan security forces, ambushing an army bus in the capital, Kabul, and storming an army recruitment center in the north of the country. At least 14 Afghan soldiers and police were killed in the two attacks, each carried out by squads of suicide bombers and gunmen.

The Afghan police and army are considered key to the West’s exit strategy, which calls for Afghan forces to take over security responsibilities across the country in the next three years. That plan was endorsed at a NATO conference last month and again last week in a White House assessment of the long-running Afghan conflict.

The Taliban movement claimed responsibility for the twin assaults on Sunday, and warned that it would continue targeting Afghan forces as well as Western troops. This year has been the deadliest of the nine-year-old war for the North Atlantic Treaty Organization force, which on Sunday announced the death of another service member, whose nationality was not immediately disclosed, in an explosion in the south.

The attack on the army bus in Kabul took place during morning rush hour on a heavily traveled road.

The Defense Ministry said five soldiers were killed in the strike, which was the most lethal attack in the capital in seven months.

The army recruiting center that was targeted in the other attack is in Kunduz, a once-peaceful northern city that has been the focus of sharply intensified insurgent activity over the course of the last year.