Six people, including a soldier, have been shot dead in Maysan, southern Iraq, after a tribal dispute over farmland escalated into violence.
Iraqi authorities said three people were shot and killed in a separate clash in the province of Kut, about 200 kilometres to the north-west.
Southern Iraq is often the site of heated disputes over land and water rights, the result of a weak legal system that sometimes fails to enforce property rights, and the mass movement of tribes over the decades, with some disputes emerging after tribes fled persecution under the former regime of Saddam Hussein.
More recently, disputes have escalated because land has deteriorated as a result of severe drought. Saad Al Zaidi, a police spokesman for the area, said the recent dispute revolved around land.
The violence in Al Uzair district, south of Amarah in the south-eastern province of Maysan, lasted several hours, Mr Al Zaidi told AFP.
The soldier killed in Maysan was from one of the two tribes and had been "on leave when the conflict broke out because of disputes over farmland", Mr Al Zaidi said.
Despite beefed-up security measures, Maysan province, which borders Iran, is a route for drug traffickers where tribal rivalry often degenerates into violence.
Amarah has also been the scene of fierce rivalry between Iraqi Shiite militias, some backed by Iran and others loyal to Shiite cleric Moqtada Al Sadr.
In May, eight people were killed in the same region when clashes between members of the same tribe broke out over farmland.
Farther north, in Wasit province, an armed clash between members of the same tribe left three people dead and three others wounded, said Ali Hussein Al Sarai of the local police force.
The violence, which occurred in the town of Al Dubuni, broke out over a dispute between two sides over the right to marry a young woman, Mr Al Sarai said.
Millions of people belong to strongly patriarchal tribes in Iraq. Violence between tribes, or within the same clan, is frequent in Iraq and often occurs without involvement by law enforcement bodies.