Pepsi-Cola North America has expanded its Mountain Dew soft drink line with the addition of a flavoured diet variety for the US market.

Diet Mountain Dew UltraViolet will be available from 10 August for a limited period and combines citrus and mixed berry flavours, the company said this week.

"Over the years, we've had fantastic success with limited time regular Mountain Dew flavoured line extensions," said Marisol Tamaro, director of marketing, Mountain Dew.  "It felt like the right time to offer the same opportunity to Diet Dew fans."

Diet Mountain Dew UltraViolet will be available nationwide for 12 weeks. The launch will be supported with a range of TV and radio advertising.

PepsiCo last week posted a drop in net sales and profits for its fiscal first half.

Net sales for the 24 weeks to 13 June fell by 3% to US$18.85bn, while net earnings slipped 2% to US$2.8bn, compared to the same period a year earlier.