Insurgent attacks in Afghanistan jumped by 50 percent in the first half of 2008 as militants crept closer to the capital and increasingly turned their guns on aid workers, a new security report said.

The data from the Afghanistan NGO Safety Office, a Kabul-based group funded by Western donors that advises relief groups on security, could fuel concern that the effort to stabilize Afghanistan is failing.

In a quarterly report released late Sunday, ANSO said it logged 2,056 insurgent attacks in the six months through June, a 52 percent increase from 1,362 incidents in the same period of 2007.