In eastern Afghanistan, U.S.-led coalition forces killed four civilians during a raid Wednesday targeting insurgent gunmen.

Reports say several militants also were killed, but the casualty toll is not yet confirmed. In a statement, the coalition said today's raid was aimed at a compound used by militants in the Mata Khan district of Paktika province. The operation targeted two men said to be responsible for planning insurgent fighters' operations.

The coalition statement says the civilians - three women and one boy - died during a U.S. air strike after troops on the ground came under fire from the militants' compound.

Civilian casualties are a sensitive issue in Afghanistan, with the country's leaders concerned that such incidents could increase support for Taliban insurgents. President Hamid Karzai has repeatedly urged international forces to use maximum caution to prevent or at least avoid civilian casualties.

Separately, Slovakia's government Wednesday approved a plan to more than double its military presence in Afghanistan.

The central European country currently has around 70 troops in Afghanistan. Under the plan, Slovakia could build up its force to roughly 250 in the next two years. Parliament must give final approval to the proposal.

Also today, the Afghan Defense Ministry says a gas cylinder exploded in a Kabul prison, killing a U.S. national, his translator and two contractors. The explosion happened at the Pul-i-Charkhi prison, which is home to hundreds of Taliban suspects.

Some information for this report was provided by AFP, AP and Reuters.