Updated

The reputation of the Afghan police has deteriorated in the south of the country in the past year, according to a U.N. survey released Thursday, despite a campaign by NATO and U.S. troops to strengthen Afghan security forces in a region seen as key to defeating the Taliban insurgency.

Countrywide, 79 percent of Afghans have a favorable view of the police — unchanged from a year ago — and 34 percent say their confidence in the police has grown in the past year, the survey said.

Improved public opinion about police in relatively safe central provinces and the capital were offset by a significant drop in the five southern provinces of Helmand, Kandahar, Zabul, Uruzgan and Nimroz.

In the south, only 48 percent of respondents said they had a "somewhat favorable" or "very favorable" opinion of the police in their area. That's down from 67 percent a year ago.

The U.S. has poured thousands of troops into southern Afghanistan in the past year in an attempt to drive Taliban out of their strongholds. The international forces have been partnered with Afghan soldiers and police at a much closer level than previously in an attempt to train up the Afghan forces and build confidence in their ability to secure the population.

This strengthening of Afghan forces is seen as key to allowing international troops to start going home. The U.S. has said it hopes to start drawing down forces in July and the Afghan government has committed to taking over responsibility for security countrywide by 2014.

But the Afghan police continue to be seen as untrustworthy by many. Sixty percent of those surveyed reported a significant level of corruption among police officers and more than 25 percent said they had seen police officers using drugs or narcotics.

The survey — conducted in early November in partnership with the Afghan Interior Ministry — included more than 5,000 adult Afghans across all of the country's 34 provinces. This was the survey's second year, so no comparisons are available before 2009.