SEGOU, Mali — American planes transported French troops and equipment to Mali, a US military spokesman said Tuesday, as Malian and French forces pushed into the Islamist-held north.

The town of Douentza had been held by Islamist rebels for four months, located 120 miles northeast of Mopti, the previous line-of-control held by the Malian military in Mali’s narrow central belt. The Islamist fighters have controlled the vast desert stretches of northern Mali, with the weak government clinging to the south, since a military coup in the capital in March last year unleashed chaos.