NATO says five of its soldiers have been killed in a roadside bomb attack in eastern Afghanistan.

Local Afghan officials said an improvised explosive device went off Wednesday near a convoy of coalition troops in the province of Ghazni.

The Taliban immediately claimed responsibility for the attack, claiming that the coalition members killed were part of a Polish convoy.

Media reports in Poland said five Polish soldiers were killed in the attack.

Separately, Afghan police said they shot and killed an attempted suicide bomber before he could detonate his explosives outside a bank in the eastern province of Khost, a stronghold of the al-Qaida-linked Haqqani militant network.

It is not immediately clear whether the would-be suicide bomber was targeting the bank or a nearby police station. Police are also looking for a possible second attacker who escaped.

Meanwhile, Afghanistan's defense ministry said Wednesday that it is making progress in training security forces ahead of an expected 2014 withdrawal of foreign combat troops.

Defense Ministry spokesperson Mohammad Zahir Azimi said the number of Afghan National Army troops now stands at 180,000. The United States and NATO say they would like to see 195,000 Afghan troops in the field by October of 2012.

International forces have already begun handing over security responsibility to Afghan forces ahead of the 2014 withdrawal.