Militants believed to be from Somalia's extremist group al-Shabab killed at least 4 police in an attack on a police post near the Somalia border, AP quoted an official as saying Saturday. About 40 armed extremists on Friday night raided a police post in Galmagalla village, a remote area that has poor communications infrastructure, said Rashid Khattor, the commissioner for Garissa county in Kenya's north east. "We have alerted all units of our security personnel including (the Kenyan military) to immediately respond to the attack," he said. He said a local chief and a school teacher were wounded in the cross-border attack. Somalia's extremist network al-Shabab claimed responsibility in updates on Twitter, saying its fighters killed five police and seized dozens of weapons and communication equipment. The militants claimed they had burned down the police post before retreating back to Somali territory. Al-Shabab has staged many attacks inside Kenya in retaliation for the Kenyan government's decision in Oct. 2011 to send troops into Somalia to battle the rebels. The Kenyan government sent troops there after several cross-border attacks and kidnappings of foreign tourists.