MOGADISHU, Somalia — At least 71 people have been killed and more than 300 wounded in ongoing fighting between rival militias in the Somali city of Kismayo, the World Health Organization said Thursday.

The clashes in the southern port city have displaced many and "continues to have a profound impact on civilians and humanitarian aid work" in the region, the United Nations health agency said.

Many of the victims suffered fractures, head and chest injuries. Nearly 40 patients had to be operated on, according to WHO.

Kismayo is currently the scene of intense, sporadic battles as rival militias fight for control of the strategic city. Somalia's central government accuses Kenyan troops stationed in Kismayo of backing one militia against others and wants the African Union —under whose auspices the Kenyans are deployed — to send a neutral force there.

Somalia's government has filed a complaint with the African Union in which it charges that the conduct of Kenyan troops in Kismayo is undermining military efforts against the Islamic militants of al-Shabab. Kenyan troops are accused of backing the Raskamboni brigade, a militia that helped them push al-Shabab out of Kismayo. The Raskamboni brigade is led by Ahmed Madobe, a key power broker around Kismayo who is not supported by Somalia's central government in the capital. Madobe's militia is fighting a group led by former warlord Barre Hirale.

Somalia's foreign ministry complained in a letter to the African Union this week that Kenyan troops in Kismayo had scuttled plans to have a united force there that is led by a Somali commander. Because of this, the letter said, "various clan factions" had formed, undermining peace and security in the wider Jubba region.

The letter said the conflict in Kismayo had given al-Shabab an "unwarranted lull at a critical time" and that momentum gathered against the militants "has come to a halt."

Kismayo is important for Kenya, which seeks a friendly buffer zone near its border with Somalia — one of the main reasons it sent troops to Somalia to fight al-Shabab in late 2011. But the rival militias now at war there appear to be interested in the economic engine of Kismayo. Its port generates large and reliable income, and has been the export point of Somali-made charcoal made illegal by the U.N.