At least 15 killed in grenade attack in northern Kenya By Noor Ali ISIOLO, Kenya (Reuters) - At least 15 people were killed in a grenade attack on Sunday in a remote village in northern Kenya where low-key clan clashes have displaced hundreds of people in the past week, the Kenya Red Cross and local officials said. Pastoralist communities in northern Kenya have long wrangled over the control of highly valuable grazing land. But the fighting, in which more than 20 villagers have been killed in the past two days in Mandera county, near the east African nation's frontier with Ethiopia and Somalia, has marked an escalation in tension. Residents say the political class in the area are using clan militia to jostle for top positions in the local administration and to settle old scores. The epicenter of the fighting is located about 800 km from the capital Nairobi. "The attackers fled towards Ethiopia but they are being pursued," said Mandera county commissioner Michael Tailel, of the militia who attacked Joroqo village in Mandera county. The Kenya Red Cross said on its Twitter feed that 15 people had been killed in the grenade attack and seven others were in critical condition. Local media reported that Kenya's Inspector General of police David Kimaiyo had summoned leaders from Mandera and the nearby Wajir county to record statements on the attacks, saying the violence was politically instigated. Although Kenya has sent in extra Kenyan security forces to the region in the past few weeks, the officers have struggled to keep peace due to the vast, harsh terrain in the region. Residents in the remote area rely on vigilante groups for security. Many homesteads have weapons to deter invaders, while herders often carry guns to protect their animals because there is barely any police presence. The region is also awash with guns due to its proximity to unstable neighbors such as Somalia, where al Qaeda-linked militants have been fighting to topple the government. Kenya's north also borders Ethiopia, where the armed Oromo Liberation Front has made sporadic incursions into the country. Hundreds of residents from the attacked village begun fleeing their homes after the attack, aid workers said. "More than 20 people have lost their lives, hundreds are fleeing their homes, the police and the military are just watching, they are doing nothing," Ibrahim Issack, a resident of Mandera, near the village hit by the grenade said. Writing by James Macharia; Editing by Alison Williams