United Nations Secretary-General Ban Ki-moon says violence in Afghanistan is getting worse.

In a new report, Mr. Ban says the number of violent incidents during the first three months of the year increased significantly compared to the same period in 2009.

The report says the number of roadside bombings jumped 94 percent, while the number of assassinations carried out by insurgents rose by 45 percent.

It also says the rate of what it describes as "complex suicide attacks" has doubled.

The report says most of the violence is taking place in Afghanistan's south and southeastern regions, and demonstrates the growing capability of terrorist networks linked to al-Qaida.

When asked about the U.N. report Saturday, a NATO spokesman said the international military force is "on the right track."

Brigadier General Josef Blotz said NATO forces expect to see progress in their fight against insurgents by August.  He said the situation is "trending in our favor" as more troops arrive in the south.

Also Saturday, NATO said international and Afghan troops killed a Taliban sub-commander and several insurgents during an operation in Kunduz province.  Officials said Mullah Abdul Razaq was involved in moving would-be suicide bombers throughout the province and coordinating roadside bombings.

NATO said forces also recovered weapons and ammunition.

Taliban militants have been increasingly targeting international forces and Afghan civilians ahead of a planned NATO push to secure southern Kandahar province.

On Friday, U.S. Secretary of State Hillary Clinton said the Afghan government and its international backers have made considerable progress toward stabilizing Afghanistan.  She also confirmed her plans to attend the July 20 conference on Afghanistan in Kabul.