KABUL (Reuters) - 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 claimed on Saturday. Four Taliban suicide bombers, dressed as police and women, attacked the main United Nations compound in Herat city, a commercial hub in Afghanistans west, on October 23. All four were killed and there were no casualties among UN staff. Sayed Ansari, a spokesman for Afghanistans National Directorate of Security (NDS), claimed one of the three detained men, identified as Noor Mohammad, had been responsible for transporting the four suicide bombers from Quetta. The bombers were taken from Quetta through southern Kandahar province to Herat, Ansari said. Ansari said the attack was directly connected to the Quetta shura, the senior Afghan Taliban leadership based in Quetta across the border from Kandahar. The attack took place under orders from Mullah Esmatullah Samangani, who is a current member of the Talibans Quetta shura and now lives in Pakistan, Ansari told a news conference. Ansari alleged that two Pakistani nationals, who he identified only as Hekmat and Muneer, were also involved in preparing the four suicide bombers in Quetta. He said the other two men who had been detained were car dealers in Herat city who had supplied a vehicle that was used in the suicide attack. He said the three were detained in Herat last week and that a fourth man, who resisted arrest, had been killed.