At least 20 insurgents were killed in Afghanistan's southeast in an operation against the Haqqani network, whose leader Washington wants designated a terrorist, the Nato-led alliance said on Thursday. Air strikes were called in after Afghan and International Security Assistance Force (Isaf) troops found dozens of insurgents in entrenched fighting positions in a mountainous area of Dzadran district in Paktia, not far from the Pakistan border, Isaf said in a statement. Washington is pressuring Pakistan to take action against the Haqqani network, a group allied with the Taliban and believed to have close links with al-Qaeda. This area is a known Haqqani network safe haven and used to stage attacks into Kabul and the Khost-Gardez pass, Isaf said.