Rebels of the Revolutionary Armed Forces of Colombia (FARC) attacked a prison in west-central Colombia, killing seven people, injuring four and allowing 23 inmates to escape, an official said Wednesday. The assault on the Picalena prison in Ibague began late Tuesday when rebels detonated two powerful blasts inside the prison, creating two holes in prison walls, said Javier Gomez, a regional public defendant. Prisoners, including some FARC rebels, escaped through the openings while rebels fired rifles at prison guards, he said. "It really is unusual that they could have explosives inside jails," Interior and Justice Minister Sabas Pretelt told Radio Caracol Wednesday. "We are investigating why there were explosives inside the penitentiary." Pretelt said Wednesday that the situation was under control at the prison after the assault. The minister said some of the fatalities were prisoners killed by guards who opened fire on them to prevent their escape. He said that although numerous FARC rebels had escaped, there were no major figures among them. A search was launched for fugitives. Gomez said a body count revealed the seven deaths, and a roll call showed 23 prisoners had fled. The four injured inmates were taken to a hospital in Ibague. --SP 2233 Local Time 1933 GMT