In Poland, a woman and her two children have been killed in a gas explosion in an apartment in the southern city of Bytom.  <br />'' <br />'' Four other people have been hospitalised. <br />'' <br />'' A spokeswoman for local firefighters, said the explosion occurred in a ground-floor apartment in downtown Bytom today. <br />''<br />''Another 17 people have been evacuated from the building where the explosion broke windows and cracked a ceiling. Seventeen teams of firefighters worked to put out the fire caused by the explosion.