Security officers in northern Kenyan border town of Mandera have arrested over 20 suspects in connection to the grenade attack that killed two policemen and injured four others on Thursday. Mandera County Commissioner Michael Toilel said on Friday that the contingent of armed officers have been deployed into the areas to carry out operation to flush out the suspected bandits following the incident. \"The security operation that was mounted by Kenya Army and the police along the border areas with the Somali managed to arrest more than 20 suspects. We are interrogating the suspects and those found culpable would be arraigned in court,\" Toilel said. During the attack early Thursday, a total of 12 vehicles were burnt down beyond recognition by the explosives hurled at the camp by the assailants who were believed to members of the Al-Qaida proxy in the neighboring Somalia. The County Commissioner said the Kenya Defense Forces have blocked all border areas between Somalia and Kenya to ensure that the suspects will not flee out of the country. He said the officers have embarked on house to house search for the suspect in order to ensure that they were brought to book. \"We have put security measures in place and we promise to arrest the suspects behind the bombing of the government building, \" said the Toilel. He said the officers have conducted thorough investigation into the attack and pledged that they will net three suspects who were injured and carried away by the bandits. Kenya has experienced dozens of attacks by unidentified people involving shootings, grenades, and other explosives since the east African nation launched cross border incursion into southern Somalia two years ago. Most of the attacks have been in Kenya\'s northern region near the Somali border, but some have been in Mombasa and Nairobi. The attack came after the Kenya was shocked by one of the worst terror attacks in the recent past at Westgate shopping mall in Nairobi on Saturday in which at 61 civilians and six security officers were killed. Al-Qaida allied Somali militants have claimed responsibility for the Westgate attack which also saw five militants killed and 11 suspects arrested for questioning. Foreign forensic experts who are investigating the Westgate incident are expected to establish the identities of the terrorists who stormed the shopping mall and opened fire on the shoppers. The investigations involve finger-printing, DNA and ballistics examination, will go on for the next seven days and will establish the identities of the slain militants.