Iraqi minister and weapons scientist are latest trophies in search for wanted men

US forces were last night holding Saddam Hussein's former finance minister, who was also a deputy Prime Minister, a further advance in the gradual process of accounting for former members of the deposed regime.

As the fate of Saddam himself remains a mystery, the handover to the US Marines by Iraqi police of the arrested Hikmat Ibrahim al-Azzawi, brings to five the number of regime members captured out of the total 55 sought by US forces.

A scientist accused of playing a key role in developing the lethal nerve agent VX has also turned himself in to the Americans.

As with Saddam Hussein's half-brother Barzan al-Tikriti, whose capture in south Baghdad by US special forces was announced on Thursday, US investigators are hoping that al-Azzawi may be able to help them establish the whereabouts of the Iraqi dictator's fortune – estimated at between $2bn and $24bn.

As finance minister, al-Azzawi was a key figure in Iraq's efforts to bust United Nations economic sanctions imposed after its invasion of Kuwait in 1990, signing a string of trade agreements in recent years.

US officials hope weapons scientist Emad Husayn Abdullah al-al-Ani, who is not on the list of 55, may be able to provide so far elusive evidence of any chemical and biological weapons programme, and possibly, of links between Iraq and the al-Qa'ida network that was behind the terrorist attacks on the US of 11 September 2001.

In 1998, US officials accused Ani of involvement with a US chemical plant in Sudan supposedly linked with Osama bin Laden. The chemical plant, bombed on the orders of President Clinton, was never proved to have manufactured chemical weapons.

The US military announced the latest detentions a day after US Central Command said Iraqi Kurds near Mosul in northern Iraq had handed over Samir Abul Aziz al-Najim, a senior official of Saddam's Baath party and also on the wanted list.

The other detained members on the list are Saddam's other half-brother, Watban al-Tikriti, and the president's top scientific adviser, Lieutenant-General Amer Hammoudi al-Saadi who gave himself up last weekend in Baghdad.

US Central Command also said yesterday that an "international terrorist" and member of the Palestinian Abu-Nidal organisation, Khala Khadr al-Salahat, had surrendered to US Marines in Baghdad.

Although the captures are a fillip to US forces, they still leave 50 of the top regime members unaccounted for, including, among many others, Tariq Aziz, the English-speaking Christian who was a deputy Prime Minister, Ibrahim Ahmad Abd'al Sattar Muhammed al-Tikriti, the armed forces chief and Hamiz Raja Shalah al-Tikriti, the airforce chief. And they also leave occupying commanders guessing about the whereabouts of Saddam Hussein himself. US experts are studying video footage broadcast by Abu Dhabi TV on Friday which the station said showed Saddam saluting a crowd of supporters in the northern Adhamiya district of Baghdad on 9 April, the day the Iraqi capital effectively fell.

In Riyadh, Saudi Arabia, yesterday foreign ministers from eight Middle East nations ended an emergency meeting with an appeal to US and British forces to leave Iraq swiftly and saying the UN should have a central role in rebuilding Iraq. They stressed that "the Iraqi people should administer and govern their country by themselves."

Meanwhile, with last week's award of a major contract to the gigantic and politically well-connected Bechtel group, the US has moved from fighting a war in Iraq to rebuilding Iraq.

In the absence of Saddam and the Baath party, US policymakers are discovering the extent to which politics in Iraq consists of clans, tribes, and religious sects. Their dangerous eddies became tragically apparent last week when the cleric Abdul Majid al-Khoei, who returned from exile in London to attempt to reconcile Shia factions, was killed by a mob in the holy city of Najaf.

Fierce debate over the political future of Ahmed Chalabi, the formerly exiled opposition leader of the Iraqi National Congress, reflects a debilitating Washington dispute between the Pentagon (pro-Chalabi) and the State Department (which mistrusts him). But it also symbolises the tensions between the exile groups and former dissidents, including religious leaders, inside the country.

In their continued attempts to prevent such tensions overwhelming attempts to introduce a stable administration, US officials intend to preside over a second meeting of former opposition groups – the first was near Nasiriyah last week – inside the country in a week's time.