KABUL, Afghanistan - A roadside bomb shattered an armored vehicle in a NATO convoy in eastern Afghanistan on Wednesday, killing five Polish soldiers in the deadliest single attack on Poland's military in the war-torn country.

Polish spokesman Jacek Sonta said in Warsaw that the soldiers were headed to Rawza, in eastern Ghazni province, when their vehicle struck the bomb.

The Taliban claimed responsibility for the attack in a text message to journalists. Taliban spokesman Zabiullah Mujahid said "a Polish tank" was blown up and all its occupants were killed.

AP Television News footage from the scene showed wreckage of what seemed to be a U.S.-made Cougar armored terrain transport vehicle. The blast appeared to have broken the 19-ton vehicle into three large pieces, which lay scattered around a crater near village homes.

Mohamad Ali Ahmadi, deputy governor of Ghazni province, said that Polish soldiers were attending a meeting in the Rawza district of Ghazni city, about 77 miles southwest of the capital Kabul.

Poland is withdrawing about 100 of the 2,600 troops it has in Afghanistan.

This year, 532 NATO service members have been killed in Afghanistan. The attack on the Polish convoy brings the number of NATO troops killed in December to 16.

Also in the east, Afghan police said they shot dead on Wednesday a would-be suicide bomber before he was able to attack a police station.

Youqib Khan, deputy police chief in Khost province, said policemen identified the would-be bomber in front of a bank next to the police station in Khost city and killed him before he could detonate his explosives vest.

Also Wednesday, an Afghan military spokesman said the country's armed forces now number 180,000 troops, a significant step toward having enough troops to replace departing coalition forces.

Defense Ministry spokesman Mohammad Zahir Azimi said the troop numbers increased by more than 40,000 in 2011. That brings the military closer to the goal of having 195,000 Afghan troops by next October. The expansion of the army and police is a critical element in NATO's exit strategy.