The first is an air force logbook that gives details of the movement of weapons of mass destruction, including the use of VX poison gas against Iran in 1988. Even more incriminating is a memo written by three senior Iraqi generals to President Saddam Hussein in 1991, listing the Iraqi rockets and biological and chemical weapons that survived the Gulf War.
General Wafiq al-Sammarai, former head of Iraqi military intelligence, who defected at the end of 1994, told The Independent: "The logbook contains details of all operations carried out by the air force and is hand-written for the sake of secrecy. It also documents the use and movement of weapons of mass destruction."
The UN has hitherto not revealed what it expects to find in the logbook other than to say that it contains details of ordnance use. President Bill Clinton signalled its importance in his speech last Sunday explaining why the United States had not launched air strikes against Iraq. He said that handing over the air force document would be a sign that Iraq was willing to comply with UN demands.
Since General Sammarai defected he has established a reputation among foreign intelligence services of providing accurate information.
The logbook, a diary of all incidents affecting the Iraqi air force, was discovered by UN inspectors on 18 July during a surprise search of an air force headquarters in Baghdad. They were only able to glance at it and were not allowed to take a copy.
General Sammarai says the logbook records the use of chemical weapons against Iran at the end of the eight-year long war with Iraq. He says: "It shows Iraq used VX [nerve gas] in the battle of Fao on 17 and 18 April 1988." Iraq has said it used mustard gas and has always denied to the UN that it succeeded in putting VX in a weapon in a usable form.
The general says the log also shows that Iraq used Sarin, an equally deadly but more volatile gas than VX, against the Kurdish town of Halabja in northern Iraq in 1988. Some 5,000 civilians were killed.
Richard Butler, head of the UN Special Commission (Unscom) on the elimination of Iraq's biological, chemical and nuclear weapons, has asked Tariq Aziz, the Iraqi Deputy Prime Minister, to hand over the documents. The UN says it wants the air force document to see if Iraq used the munitions it said it did during the Iran-Iraq war, or has kept them hidden.
General Sammarai says that the second document sought by the UN dates from May 1991 and is a memorandum drawn up by three senior Iraqi officers: Lieutenant-General Hazen Abdel Razaq, Major-General Mustafa Kemal and Lt-Gen Mozahem Saeb al-Tikriti. He says: "It gives exact information about what remained of Iraq's weapons of mass destruction after the Gulf War."
The document says that at the time Iraq had about 100 usable scud rockets. It also mentions warheads containing VX. General Sammarai says: "The regime in Iraq is not ready to hand over these documents because this would be a political catastrophe."
He says that just before the battle of Fao, where Iraq lost 53,000 soldiers, Iraq considered placing VX warheads on scud missiles that it was firing at Tehran. After victory at Fao, Iraqi leaders thought there was no reason to attack the Iranian capital with the gas.
General Amer al-Saadi, a senior adviser to President Saddam, said earlier this week that Iraq was prepared to discuss the documents Mr Butler was demanding.
Human rights investigators called yesterday for an international investigation into claims that Bosnian Serb forces may have fired nerve gas at Muslims fleeing Srebrenica in 1995.
Human Rights Watch spoke to 35 survivors of the attack and said their accounts suggest Bosnian Serbs fired BZ nerve agent at the refugees. Officially called 3-Quinuclidinyl Benzilate, BZ is a nerve agent similar to the drug LSD that produces hallucinations in victims.