On 15 February 2011, Brazil assumed command of the Maritime Task Force (MTF) of the United Nations Interim Force in Lebanon (UNIFIL). On 4 October the Brazilian Ministries of Defense and Foreign Relations informed authorities that Brazil was sending a Navy vessel with up to 300 crew members, equipped with an aircraft, to join the fleet in Lebanon and the vessel was authorized by the National Congress. On 25 November 2011 the frigate União with 239 officers and sailors aboard joined the task force, bringing to nine the number of vessels assisting the Lebanese Navy in monitoring Lebanese territorial waters.

The frigate served as the flagship for Rear Admiral Luiz Henrique Caroli of Brazil who had been Commander of UNIFIL-MTF since February.

Brazilian Corvette Barroso

On 10 April 2012 the frigate Liberal left Rio de Janeiro bound for Lebanon to join the force.[60] It was relieved in January 2013 by the frigate Constituição which joined a multinational group comprising nine ships; three from Germany, two from Bangladesh, one from Greece, one from Indonesia and one from Turkey. The crew comprised 250 military officials. The return to Rio was scheduled for August 2013.

On 8 August 2015 the corvette Barroso left Rio de Janeiro to replace União and later that month carried out maritime interdiction operations and provided training to the Lebanese Navy. On 4 September 2015 it rescued 220 Syrian migrants in the Mediterranean Sea, as reported by the Ministry of Defense in a statement released on its website. The Brazilian ship was sailing towards Beirut in Lebanon when it received an alert from the Italian Maritime Rescue Coordination Centre (MRCC) about a sinking vessel taking immigrants to Europe.