The United Nations agency responsible for decommissioning weapons in Eastern Europe has criticised arms exports to Iraq.
File On 4's Allan Urry with a stockpile of weapons near Sarajevo, Bosnia
Seesac has told File On 4 that the sale of large numbers of guns from Bosnia has compromised its operation.
There are also concerns that some pistols flown from the UK which were intended for Iraqi police are now in the hands of insurgents.
A Foreign Office Minister is being pressed for details of security checks.
When Saddam Hussein was toppled from power, about 20 million weapons were estimated to be in Iraq.
Millions more have come in since because of the continuing conflict.
Paradoxically, back in 2004 the emerging Iraqi security forces were struggling to get weapons, ammunition and other equipment they needed.
The US struck a deal with the Bosnian authorities to open up its stockpiles of weapons left over from the conflicts in the former Yugoslavia in the 1990s.
It aimed to send these weapons to help Iraq's new army.
But the UN is involved in a programme of trying to destroy those weapons with the co-operation of the host nation authorities.
FILE ON 4
Tuesday, 23 May 2006
BBC RADIO 4, 2000 BST
Repeated Sunday 28 May, 1700 BST
The EU would also prefer to see those guns put out of harm's way, with Britain among the countries giving money to assist that process.
The head of Seesac, the UN agency trying to develop safe and effective weapons policies across the Balkans, says they were not consulted about the US deal and that it has made arms control more difficult.
Adrian Wilkinson told File On 4: "We have a range of projects in the region to destroy surplus weapons to counter the risks of proliferation, to reduce the chances of them turning up on the grey and the black markets and fuelling conflict.
"And yet it is very difficult for us to negotiate with governments in the region to destroy their surplus weapons whilst they feel that the United States is going to come along and buy them to re-equip the new armed forces of Iraq."
File On 4 has learnt that about 200,000 weapons and 40 to 50 million rounds of ammunition have been exported by Bosnia to Iraq under this deal.
Some experts say there is a need for this amount of weapons in Iraq to help protect the security forces.
But organisations like Amnesty International are concerned about the complexity of this procurement operation.
The Americans have effectively appointed a main contractor - a small business based in Alabama - which has then had to subcontract middlemen, traders and brokers all over Europe.
Amnesty says that this makes it hard to know who is buying what and what has been sent where.
One case investigated by File On 4 highlighted this difficulty.
The programme has been shown paperwork about a consignment of 20,000 AK-47 type assault rifles by Eufor, the EU peacekeeping force which provides a safeguard for Bosnian weapon transfers.
It shows they were imported by a company in the north of England called York Guns Limited which sells shotguns and sporting rifles.
Its managing director Gary Hyde would not be interviewed but denied having imported the AK-47s. A third party dealer had legally brought them into the UK, he claimed.
Foreign Office Minister Dr Kim Howells also refused to be interviewed about the matter. He has been questioned by MPs about a different company who exported 20,000 Italian Beretta pistols from the UK to Iraq.
This is part of the same drive to re-equip Iraqi security forces and there have been concerns that some of these sidearms have fallen into the hands of insurgents.
MPs on the Quadripartite Committee which scrutinises Britain's arms exports asked Dr Howells for clarification.
The committee chairman, Labour's Roger Berry, said: "I wasn't satisfied with the response to our questions at the public evidence session.
"That's why I'm pursuing the matter further with the Foreign Office.
"I don't think that people in the UK would want the UK Government to agree to export licences that would result effectively in weapons going through the Iraqi police into the hands of insurgents and then being used to kill British soldiers.
"The question I want to ask is 'What measures has the UK government taken or not taken in relation to the allegation that the weapons have been diverted from the Iraqi police to insurgents?'
Amnesty called for tougher laws to control the arms trade
"That, for me, is the number one question."
A Foreign Office spokesman told the BBC in a statement that all export licence applications were assessed rigorously, including consideration of the internal situation in the destination country and the risk of diversion to an undesirable end use.
It said staff in Baghdad had found no firm evidence to support the concern about the weapons falling into the wrong hands.
However, File On 4 has obtained copies of Italian prosecutors' documents which show otherwise.
The prosecutors' office in Brescia, the hometown of Beretta where a criminal investigation is taking place into aspects of this deal, confirmed that serial numbers on pistols found in possession of what are described as "hostile forces" relate to the consignment sent from Beretta to the UK and then onwards to Iraq.
File On 4: BBC Radio 4, Tuesday, 23 May 2006 at 2000 GMT and repeated on Sunday 28 May, 2006 at 1700 GMT. Or listen online - see links on the right hand side of this page.