epa04696765 A member of the Afghan police forces guards the scene where gunmen stormed the office of the Attorney General in Mazar-e-Sharif, Afghanistan, 09 April 2015. According to reports gunmen dressed in military uniforms stormed the office of the provincial public prosecutor in the northern Afghan city of Mazar-e-Sharif, killing at least five people and injuring 25 others. EPA/SAYED MUSTAFA

Mazar-i-Sharif, Afghanistan - Taliban suicide attackers wearing military uniforms stormed a court complex in Afghanistan's relatively tranquil north on Thursday, killing at least three people and wounding scores of others in an assault highlighting the country's fragile security situation.

The ongoing assault in Mazar-i-Sharif city comes just before the start of the Taliban's traditional spring offensive, set to be the first fighting season when Afghan security forces battle insurgents without full NATO support.

Explosions rang out as assailants wearing suicide vests lobbed grenades and exchanged gunfire with Afghan security forces, setting ablaze one of the buildings in the compound, according to an AFP reporter at the scene.

“In the morning a group of three to five armed attackers in military uniforms and equipped with suicide vests stormed the Appeals Court complex,” the Afghan interior ministry said in a statement hours after the siege began.

“Police reinforcements reached the site of the attack and immediately launched operations against the insurgents. The clean up operations are underway.”

At least three policemen were killed, the acting governor of the affected Balkh province, Atta Mohammad Noor, said in a statement.

Thirty-one wounded people, some in critical condition, were brought to the local public hospital.

“Police, prosecutors, court staff, women and children were among those wounded,” Noor Mohammad Faiz, a senior doctor at the hospital, told AFP.

Militant attacks are relatively rare in Mazar-i-Sharif, a city well-known as a melting pot of diverse cultures and religious influences where liberal attitudes coexist with conservative traditions.

Nearly five hours after the attack started, reports of blood shortages in hospitals emerged, with urgent appeals for donors circulating on social media.

The Taliban claimed responsibility for Thursday's assault, which underscores Afghanistan's precarious security situation as US-led foreign troops pull back from the frontlines after a 13-year war against the Taliban.

“Our mujahideen have carried out a martyrdom attack... in Mazar-i-Sharif city,” Taliban spokesman Zabihullah Mujahid told AFP by telephone.

“Heavy fighting is going on between our mujahideen and Afghan forces in the area.”

The attack comes a day after an American soldier was killed by an Afghan counterpart in eastern Afghanistan, the first insider attack since Washington announced a delay in troop withdrawals from the country.

NATO's combat mission formally ended in December but a small follow-up foreign force has stayed on to train and support the local security forces.

President Barack Obama last month reversed plans to shrink the US force in Afghanistan this year by nearly half, an overture to the country's new reform-minded leader, President Ashraf Ghani.

Hosting Ghani at the White House for their first presidential head-to-head, Obama agreed to keep the current level of 9,800 US troops until the end of 2015.

The Taliban, who have waged a deadly insurgency since they were ousted from power in late 2001, warned that the announcement would damage any prospects of peace talks as they vowed to continue fighting.

Taliban insurgents have already stepped up suicide attacks on government targets following an Afghan army offensive that began in southern Helmand province more than two months ago.

The up-tick in attacks has taken a heavy toll on ordinary Afghans.

The number of civilians killed and wounded in Afghanistan jumped 22 percent in 2014, a recent UN report said, as NATO troops withdrew from combat.

The United Nations Assistance Mission in Afghanistan attributed the rise to an intensification in ground fighting, resulting in a total of 10 548 civilian casualties last year.

Afghan forces are currently bracing for what is expected to be a bloody summer push by the Taliban and the government has also raised the ominous prospect of the Islamic State making inroads into Afghanistan.

AFP