Chrysler Group said its vehicle sales in March were the best since December 2007, and estimated the industry's annual sales rate last month was 15.6 million.

Chrysler, a unit of Italian automaker Fiat SpA , said March sales totaled 171,606 vehicles, up 5 percent from 163,381 a year earlier. The Fiat, Dodge and Ram Truck brands all posted increases.

Chrysler's estimate of the industry's seasonally adjusted annual rate in March is in line with an average SAAR of 15.3 million from a group of analysts polled by Thomson Reuters. Chrysler's total includes about 300,000 heavy-duty vehicles, while the Thomson Reuters poll excluded such vehicles.

Ram Truck sales rose 24 percent in March, reflecting strong demand for the full-size Ram pickup, which received an extensive makeover for the 2013 model year.

Dodge sales were up 15 percent, led by double-digit increases for the Avenger, the Challenger and the Durango.

Sales of the compact Dodge Dart sedan topped 8,000 for the first time since the car was introduced last summer.

Sales of the Fiat 500 rose 3 percent to 3,807.

Jeep sales dropped 13 percent in March. Chrysler phased out the Jeep Liberty last fall and won't start ramping up production of its replacement, the 2014 Cherokee, until this summer. The automaker also began phasing in production of the 2014 Grand Cherokee, which has undergone a facelift.

Chrysler brand sales fell 2 percent, with the biggest decline posted by the full-size Chrysler 300 sedan.

(Reporting By Paul Lienert in Detroit; editing by John Wallace)