KABUL, Afghanistan -- Taliban fighters stormed a government building in eastern Afghanistan after killing two police guards on Monday, the most serious in a wave of attacks marking the start of the insurgents' annual spring offensive. In the Taliban heartland in the south, an attack on a police checkpoint in Helmand province killed nine policemen.
Also Monday, rockets hit the grounds of the Kabul international airport but caused no damage. Rockets also struck the NATO base at Bagram, just north of the Afghan capital, causing minor damage, the alliance said.
The Taliban offensive comes at a sensitive time this year, against the backdrop of the country's presidential election. Militants have also stepped up terror attacks to sow insecurity and weaken the government as international forces prepare to withdraw by the end of this year.
The attack on the provincial justice ministry building in the city of Jalalabad came around 9 a.m., just as employees were arriving for work, said Nangarhar provincial government spokesman Ahmad Zia Abdulzai.
The attackers shot the guards, broke in and took over the building but it was unclear how many people may have been inside when the militants took it over.
Afghan police and army forces arrived at the scene shortly afterward, surrounded the building and were engaging in sporadic exchanges of gunfire with the militants inside, said Gen. Fazel Ahmad Sherzad, the provincial police chief of Nangarhar province.
Deputy Interior Minister Gen. Mohammad Ayub Salangi said in a message posted to his Twitter account that the attack involved three militants, and that the police killed one of the attackers.
Taliban spokesman Zabihullah Mujahid claimed responsibility for the attack in an email to reporters but provided no further details. Last week, the Taliban said they would launch their annual spring offensive on May 12.
In southern Helmand province, the Taliban killed nine policemen in an attack on a checkpoint in the Sangin district, district governor Sulaiman Shah Sarwani said.
Elsewhere in the east, groups of militants, including some on motorbikes, attacked police checkpoints, killing three people and wounding eight. Those attacks happened on the outskirts of the city of Ghazni in the province by the same name, said deputy provincial governor, Mohammad Ali Ahmadi. Two women and a policeman were killed, while two policemen and six civilians, including three children, were wounded, added Ahmadi.
No one immediately claimed responsibility for those attacks.
Elsewhere in Jalalabad, attackers targeted a police vehicle and detonated a roadside bomb, wounding six people, including two policemen.
In the capital, Kabul, two rockets fired from unknown location landed inside the perimeter of the city's international airport without causing any damage, Kabul police spokesman Hashmat Stanikzai said.
To the north of the city, four rockets struck the Bagram military airbase, 30 miles from Kabul. The projectiles hit the Bagram Airfield around 3 a.m., resulting in minor damage to equipment and a building, said the international coalition.
In the presidential election, final results of the first round of voting, held April 5, are scheduled to be announced on Wednesday. The two top vote-getters are widely expected to face a runoff later this month.