KABUL: Afghan security forces have detained three insurgents they blame for an attack on a UN compound last month and believe they have links to Afghan Taliban leaders based in Pakistan, security officials said on Saturday. Four Taliban suicide bombers, dressed as police and women, attacked the main UN compound in Herat city, a commercial hub in Afghanistan's west, on Oct. 23. All four were killed and there were no casualties among U.N. staff. While the attack was repelled successfully, it caused concern for Afghan and NATO-led forces because Herat, once largely stable, is seen as an early candidate for the transfer of security responsibility from foreign forces to Afghans. Sayed Ansari, a spokesman for Afghanistan's National Directorate of Security (NDS), said one of the three detained men, identified as Noor Mohammad, had been responsible for transporting the four suicide bombers from Quetta in Pakistan. The bombers were taken from Quetta through southern Kandahar province, the birthplace of the Taliban, to Herat, Ansari said.