More Than 70 Dead in Al-Shabab Attack in KenyaHundreds of students are unaccounted for after al-Shabab militants attacked a university in northeastern Kenya, killing more than 70 people and wounding more than 60 others, the internior minister said. The gunmen stormed the campus of Garissa University College shortly after 5 a.m. Thursday and according to police, "indiscriminately" opened fire. More than 12 hours after the attack, Kenya's interior ministry said two of the gunmen who attacked a college in northeast Kenya have been killed. Kenya's Disaster Operations Center said all staff members and about one-third of the students are accounted for, leaving the status of another 535 students unknown. The agency said staff members were helping to track down students. Witnesses said the assailants began the attack near the classrooms and then worked toward the residence halls, adding an undetermined number of people are being held hostage. A reporter for VOA's Somali news service in Garissa said tanks were headed to the area and planned to attempt a rescue mission. The Kenya National Disaster Operation Center said 280 of the university's 815 students have been accounted for, and efforts are underway to track down the rest. The disaster agency said on Twitter that three of four dorms have been evacuated, with the gunmen cornered in one dorm. No further details were immediately available and Kenya Defense Forces have surrounded the area, journalists said, impeding their access. Revenge attack Al-Shabab claimed responsibility for the attack a few hours shortly after it began Thursday morning. In a statement, the Islamist militants said the attack is revenge for Kenya's troops fighting in Somalia. Witnesses said the attackers were asking students whether they are Christian or Muslim. A spokesman for the militant group said its fighters are holding Christian hostages inside the university residence but have released all the Muslims. Another spokesman told the French news agency that the group's mission is to "kill those who are against the Shabab." A statement from Kenya's police chief said the attackers fired “indiscriminately” inside the Garissa University College campus and gained entry into the students' hostels after being engaged by security officers. Kenya's Red Cross said 65 casualties have been taken to a local hospital, most with gunshot wounds. Four are in critical condition. The Red Cross also said two soldiers and one civilian have been airlifted to Nairobi. Student details attack Witnesses said students in campus housing were awakened by the sound of gunfire. Student Mercy Chebet told VOA that she and other students woke to the sounds of gunfire about 5 a.m. Thursday and evacuated the dormitories as the gunmen approached. “It started in the classes and we were in the hostels sleeping, so when we heard the bullets, we just moved out of the hostels and ran to the field,” Chebet said. “When we were in the field, they came to the hostels and they were shooting where we were." She said the gunmen then moved into the dormitories and began firing. She said she spoke by phone to some friends still inside. “They're inside, they are being held hostage and the policemen are outside. I don't know what will happen next,” Chebet said. Collins Wetangula, the vice chairman of the student union, told The Associated Press he was preparing to take a shower when he heard gunshots coming from Tana dorm, which hosts both men and women, 150 meters (yards) away. The campus has six dorms, he said. He said that when he heard the gunshots he locked himself and three roommates in their room. When the gunmen arrived at his dormitory he could hear them opening doors and asking if the people who had hidden inside whether they were Muslims or Christians. “If you were a Christian, you were shot on the spot,” he said. “With each blast of the gun, I thought I was going to die.” The gunmen then started to shoot rapidly and it was as if there was an exchange of fire, he said. “The next thing, we saw people in military uniform through the window of the back of our rooms who identified themselves as the Kenyan military,” Wetangula said. The soldiers took him and around 20 others to safety. Threat letter The University of Nairobi warned its students last week that al-Shabab was planning attacks on Kenyan institutions, including a "major university." Garissa is located about 370 kilometers (230 miles) east of Nairobi. In an email obtained by VOA with the subject "TERROR THREAT" dated March 26, the University of Nairobi's security office said information about a possible attack was "being processed by the relevant government agencies." It is not clear yet that Garissa University received or posted the same warning. The town of Garissa, in northeastern Kenya, is about 200 kilometers (125 miles) from the border with Somalia and has, in recent years, been the site of sporadic gun and grenade attacks blamed on al-Shabab. Al-Shabab is known for assaults on large buildings, such as the Westgate mall in Nairobi in 2013, and Somalia's presidential palace, which it attacked twice last year. The Westgate attack killed more than 60 civilians. Last week al-Shabab claimed responsibility for a deadly siege on a Mogadishu hotel in which at least 24 people, including six attackers, were killed. That attack lasted more than 12 hours as Somalia's security forces tried to dislodge gunmen who had taken control of parts of the Maka-al-Mukarramah hotel in the Somali capital. Mohamed Farah Shire contributed to this report from Garissa. Some material for this report came from Reuters and AP.