A senior U.S. official visiting Afghanistan says violence in the country is likely to increase this year as NATO-led foreign forces expand into new areas where Taleban insurgents are active.

Assistant Secretary of State for South and Central Asia Richard Boucher says insurgents will try to test foreign troops as NATO spreads into southern and eastern Afghanistan later this year. He spoke Monday in the Afghan capital, Kabul.

Boucher also says violence could intensify as the Afghan government takes on drug traffickers in areas it does not yet control.

NATO peacekeepers are currently deployed in northern and western Afghanistan. As part of the NATO expansion, U.S. forces in the country will come under NATO command.

The United States plans to reduce its military presence in Afghanistan from 19,000 troops to about 16,000 this year. Despite the troop reduction, Boucher says the U.S. will maintain a significant presence in Afghanistan for a "long time to come."

Some information for this report was provided by AFP and AP.