KABUL, Afghanistan — A suicide bomber struck a bus of army recruits in eastern Afghanistan, killing at least 12 people and wounding dozens, officials said on Monday.

The Afghan Defense Ministry said in a statement that all those killed in the attack, at 4 p.m. in the Surkh Rod district of Nangarhar Province, were army recruits, and that at least 26 people were wounded. Attaullah Khogyani, a spokesman for the governor of Nangarhar, put the number of injured at 38.

“The bus was coming to Kabul from Jalalabad city when a bomber riding a Zarang three-wheeler blew himself up,” the Defense Ministry statement said.

The Afghan Army, which has struggled with casualties and attrition as it has taken the combat lead after NATO’s drawdown, recruits heavily in the east and north of the country. The army and the police lost a combined total of about 6,000 men in 2015, nearly half of those casualties coming in the southern province of Helmand, which is the country’s largest province both in terms of territory and opium production.