Malian troops killed people suspected of siding with Islamist rebels, while the insurgents are responsible for the deaths of soldiers earlier this month, according to Human Rights Watch and Amnesty International.

Soldiers executed at least 13 men in the then rebel-held towns of Kona and Sevare on the eve of a French military campaign to regain control of northern Mali, New York-based Human Rights Watch said in a statement published on its website Friday .

At least seven Malian soldiers were killed by Islamists in the same area, the group said.

The Malian army has committed “serious human rights abuses,” London-based Amnesty said in a separate statement Friday.

Eyewitnesses in the town of Sevare said “more than two dozen civilians” suspected of supporting the Islamists had been executed, according to Amnesty.

Modibo Traore, a spokesman for Mali’s army, declined to immediately comment when called Friday.

The groups urged the Malian authorities to investigate the abuses and respect international humanitarian law, according to the statements.

The central Malian town of Kona was attacked on Jan. 9 by rebel groups including al-Qaida in the Islamic Maghreb, prompting a French military intervention over widespread concern the militants might try to overrun the capital, Bamako.