Brussels  - Militant attacks in eastern Afghanistan have increased 50 per cent over the last year, and NATO officials fear that deals struck between the Pakistani government and tribal leaders may have contributed, a NATO spokesman said Wednesday.

NATO forces operating in the International Security Assistance Force (ISAF) in Afghanistan recorded 50 per cent more militant attacks in the east of the country in April 2008 than in April 2007, NATO spokesman James Appathurai told journalists at NATO's Brussels headquarters.

That puts the level of violence there at close to the highest level it reached in the whole of 2007, he said.

"There is real concern in NATO that this is at least in part due to agreements that have been struck with militants on the other side of the (Afghanistan-Pakistan) border," he said.

"There are real concerns that (the agreements) may be leading to higher levels of extremist and militant activity inside Afghanistan," he said.

In particular, deals stuck between the Pakistani government and tribal leaders in the country may have allowed militants in Afghanistan to set up "safe havens" in Pakistan, allowing them to recuperate between missions and use Pakistan as a "launching pad" for further attacks in Afghanistan, he said.

NATO has no intention of intervening in Pakistani internal politics, but it will "communicate its concerns" to the Pakistani authorities, Appathurai said.

NATO Secretary General Jaap de Hoop Scheffer hopes to travel to Islamabad soon for talks on regional security, he said.

NATO has been in command of the UN-mandated ISAF since 2003. It maintains some 47,000 troops in the country. (dpa)