The United Nations on Monday condemned a suicide attack in Sri Lanka which killed 28 people and wounded 60 at a refugee registration center in the embattled northern part of the country. An estimated 20 soldiers were killed along with eight women and children when a female suicide bomber blew herself up while being frisked by soldiers processing civilians, according to the Sri Lankan military. “The U.N. reiterates that civilians must be distinguished from combatants, and protected from the fighting,” the U.N. Resident/Humanitarian Coordinator in Sri Lanka said in a statement. “It calls once again on the Liberation Tigers of Tamil Eelam (LTTE) to separate its forces from civilians under its control.” An estimated 250,000 civilians are trapped in the middle of a Sri Lankan military offensive aimed at routing the rebel LTTE group.