Islamabad, April 9 (Inditop.com) At least 18 militants were killed and four arrested when security forces repulsed an attack on their checkpoint in northwestern Pakistan, a media report Friday said.

The exchange of fire took place in Bezot Khel village in the Orakzai tribal district on the night between Thursday and Friday when some 40 militants attacked the checkpoint, Online news agency reported, quoting sources.

The troops destroyed three hideouts of the militants and captured a large quantity of arms and ammunition.

A security personnel was also injured in the fighting. The Orakzai offensive has become intensive since late March, in which over 300 militants have been killed or injured.

More than 80 percent of the people have left the area and moved to Hangu and Kohat cities after the security forces asked them to evacuate the area, the sources added.

Large numbers of Tehrik-e-Taliban Pakistan (TTP) fighters fled from their South Waziristan strongholds and moved into the Orakzai area just before the security forces launched an operation against them last October.