Five members of Massoud Barzani's party were also briefly held at the office, formerly used by the intelligence services of Saddam Hussein's deposed regime, in the upmarket Mansur neighborhood.

One of the five, Haidar Zaid, told reporters the soldiers also confiscated 60,000 dinars (50 dollars).

Zaid said the soldiers handed them a written request to report to a US army center in a week's time.

"If the weapons are duly registered, they will be returned. If not, they will be destroyed," the militants were told, according to Zaid.

US-led coalition forces had so far mainly raided premises of the Badr Brigade, the armed wing of the main Iraqi Shiite Muslim movement, the Supreme Assembly of the Islamic Revolution in Iraq (SAIRI), and arrested 20 SAIRI members in the runup to a June 15 deadline for Iraqi militias to lay down their weapons.

The coalition arms controls which will come into force after a two-week amnesty period allow private individuals to keep light weapons in their homes and businesses, up to and including Kalashnikovs.

But separately it requires all Iraqi factions to disarm their militias, outside the three northern provinces still held by the KDP and the Patriotic Union of Kurdistan (PUK), two Kurdish former rebel groups which fought alongside the coalition during the war that toppled Saddam Hussein two months ago.

WAR.WIRE