Since late 2011, Kenya has seen an upsurge in violent terrorist attacks. Kenyan government officials asserted that many of the murders and blasts were carried out by Al-Shabaab in retaliation for Operation Linda Nchi, a coordinated military mission between the Somali military and Kenyan military that began in October 2011, when troops from Kenya crossed the border into the conflict zones of southern Somalia. The Kenyan government has deployed its forces under the wider African Union Mission to Somalia, and announced in March 2012 that it would be sending 5,000 troops to join the coalition.