Toyota Motor Corp. says its May sales in the U.S. rose 7 percent on strong demand for its Lexus luxury brand, but the increase lagged behind rivals.

The Japanese automaker says Lexus sales jumped 31 percent due to a slate of generous incentives designed to spur sales following the recall of the GX 460 SUV. GX sales more than doubled during the month.

But sales of Toyota brand vehicles rose only 3.6 percent, while sales of some sedans like the Camry and the Avalon declined.

Toyota has been using heavy incentives on its Toyota brand cars and trucks to drum up sales after the company recalled millions of vehicles due to faulty accelerator pedals. But May's mixed results indicate the incentives could be losing their effectiveness.