KABUL, Afghanistan — A roadside bomb struck a police van in eastern Afghanistan on Saturday, killing five police as they were on their way to a training session, authorities said.

Seven other police were wounded in the early morning blast in Paktika province, a statement from the provincial governor's office said.

The van was taking the officers to a training center in Janikahil district for exercises between the Afghan National Police and the village-level Afghan Local Police, separate branches of the security forces that international troops have been training. Among the five dead were two national police and three local police.

Bombings, assassinations and gun battles have soared in recent months. The Taliban and other militants have stepped up attacks as Afghan police and soldiers take over full responsibility for security and international forces draw down. The intense militant campaign has pushed violence to levels matching some of the worst of the 12-year-old war.

The Afghan defense minister has urged a group of new soldiers to show unity and pride as part of the army that is taking over the lead.

Gen. Bismullah Khan Mohammadi told 3,000 graduates of Afghan National Army training Saturday that the upcoming transfer of security responsibility nationwide is a day the "Afghan people have been waiting for years."

The minister praised the army for recruiting soldiers from all of Afghanistan's ethnic groups, noting that a single battalion had ethnic Tajiks, Pashtuns, Hazaras and Uzbeks. He urged the graduates to unite to fight insurgents.

Worries of Afghan security forces fragmenting along ethnic lines have been one of many concerns about Afghanistan's future. Most foreign combat troops are leaving next year, more than a decade after the U.S.-led invasion to oust the Taliban regime.