KABUL, Nov 6: Afghan security forces have detained three militants they blame for an attack on a UN compound last month and believe the arrested men have links with Afghan Taliban leaders based in Pakistan, security officials said on Saturday.

Four Taliban suicide bombers, dressed as police and women, attacked the main United Nations compound in Herat city, a commercial hub in Afghanistan's west, on Oct 23. All four were killed and there were no casualties among UN 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.

The pace and scope of such security transfers will determine when and how many foreign troops can leave Afghanistan. US President Barack Obama, who will review his Afghanistan war strategy next month, has promised to begin drawing down US forces from July 2011, if conditions on the ground allow.

Sayed Ansari, a spokesman for National Directorate of Security, said one of the three detained men, identified as Noor Mohammad, had been responsible for transporting the four suicide bombers from Quetta.—Reuters