Group reported that the Kenya Defence Forces "divulges little about which and how many forces are involved, though prior to January, it appears to have been less than 2,000", or two battalions. According to the Center for Strategic and International Studies, the two battalions, which crossed into Somalia on 16 October 2011, numbered 2,400 troops. Writing in 2015, academics David Anderson and Jacob McKnight stated that at the operation's peak "more than 6,000 security personnel were deployed, including the Kenya Police and its General Service Unit, the Administration Police (another paramilitary unit), and units from the Kenya Air Force". Al-Shabaab The Al-Shaabaab Islamist group is the main target of the operation. Al-Shabaab officially denied involvement in any of the kidnappings. Sheikh Ali Mohamud Rage, a spokesman for the group, said that its fighters would attack Kenya unless the Kenyan troops are withdrawn. He also claimed that bombardment by Kenyan aircraft had caused damage to infrastructure and civilian casualties. According to Al Jazeera, Al-Shabaab have attempted to capitalise on the incursion by depicting itself as a resistance force fighting foreign occupiers and urged local residents to take up arms against the Kenyan soldiers. According to the Kenyan government, the organisation is supported by Eritrea. Somalia On 18 October, President of Somalia Sharif Ahmed and other TFG officials hosted a Kenyan delegation in Mogadishu where Somalia's Defence Minister Hussein Arab Isse and Kenya's Minister of Defence Mohamed Yusuf Haji agreed to collaborate against Al-Shabaab. On 24 October, Ahmed again stated that although he welcomed Kenyan logistical support, he was against the Kenyan military presence, contradicting the agreement made on the 18th. He and the Somali Prime Minister Abdiweli Mohamed Ali issued a joint statement on 27 October denying any agreement between the TFG and Kenyan government to allow the Kenyan incursion into Somalia, a stance criticised by other TFG officials. A joint communique issued on 31 October by the Prime Ministers of Somalia and Kenya on behalf of their respective governments noted "the current operations are being led by the TFG of Somalia Forces with the support of the Kenyan Defence Forces". United States According to The Washington Post, the US Air Force has been sharing surveillance data with the Kenyan military that it gathered via unarmed MQ-9 Reaper unmanned aerial vehicles (UAVs) flying out of Arba Minch in southern Ethiopia. The UAVs have been used for monitoring military activities in southern