Mogadishu - Somalia's prime minister has fired three Cabinet ministers as his government faces stiff challenges from the opposition.

Prime Minister Hassan Ali Khaire on Thursday announced the replacement of Foreign Affairs Minister Yusuf Garaad Omar with Ahmed Isse Awad, a former ambassador to Washington.

Khaire also replaced the interior minister and trade and industries minister.

Opposition parties in the Horn of Africa nation have been trying to capitalise on recent security incidents, accusing the government of shortcomings in a bid to unseat the prime minister. The country is still recovering from an October truck bombing in the capital that killed 512 people and was blamed on the al-Shabaab extremist group.

Somalia's government has accused some opposition politicians of attempting to overthrow it with the support of foreign countries.