The Somali extremist group
The attack on Bishaaro Guest House was part of a campaign to kill "unbelievers" in Kenya, the Islamist group said. Shabab, affiliated with Al Qaeda, claimed 15 were killed, while authorities put the toll at 12.
The attackers reportedly used explosives to blow open the metal front doors of the hotel before bursting in and shooting the victims.
Hours later, the group claimed responsibility for another major attack within Somalia when a suicide bomber with a truck carrying explosives slammed into the gate of a military base of the U.N.-funded African forces fighting Shabab, AMISOM.
The base in Beledweyne, north of the capital, Mogadishu, was occupied by soldiers from Djibouti, an important U.S. ally in the volatile Horn of Africa. Gunmen then attacked the base, a strategy successfully used in past attacks, including an attack against Kenyan forces in El Ade, southern Somalia, in January, which killed some 180 soldiers, Kenya's worst military loss.
Authorities have not announced how many soldiers died in the Beledweyne attack Tuesday.
The Shabab group has repeatedly targeted Kenya because of the country's military role in Somalia, as well as other countries involved in the force, including Uganda. Kenya invaded Somalia in 2011 after a spate of attacks and kidnappings in northern Kenya.
The victims in the Mandera guest house attack included 11 men and one woman. Ten of those killed in the early hours of the morning were teachers from other parts of Kenya, in Mandera to stage plays for students about books that have been set as part of the high school curriculum, local officials told Kenyan media.
One survivor, teacher Veronica Wambui, told Kenya's Nation Media she heard explosions at around 2.30 a.m. before attackers entered and shot her colleagues.
She was shot at three times, but managed to hide in a storeroom with other colleagues. Another blast went off, and part of a wall collapsed on her and others.
"I could see the lights from the [flashlight] when they were checking out the room but the collapsed wall had covered me," Wambui told the Associated Press later, speaking from the hospital. She received a bullet wound in her hand and injuries to her legs.
It was the second attack in three weeks in Mandera, a volatile border town. In an Oct. 5 attack, five Christians were beheaded, with Shabab claiming responsibility.
Shabab, fighting the U.N.-supported Somali government, has staged several major attacks in Kenya in the past, usually questioning people to see if they are Muslims or Christians, and sparing the Muslims. Its worst attack in Kenya occurred in April 2015 at a university in Garissa, in northern Kenya, where 147 people were killed, mostly Christian students from other parts of Kenya. In September 2013, Shabab gunmen attacked the upscale Westgate shopping mall in the capital, Nairobi, killing at least 67 people.
Shabab has lost a series of commanders and has seen some of its followers split off to form a faction loyal to the Islamic State, but it still remains capable of carrying out devastating attacks, as well as drive-by shootings and assassinations.