A year ago, the UN said it had evidence Iraq had destroyed all its remaining Scud missiles. But the UN has changed its view abruptly, following evidence from a senior Iraqi defector that the Iraqis had built some Scuds themselves rather than relying exclusively on imports from the former Soviet Union.
Rolf Ekeus, who chairs the UN Special commission on Iraq told a US Senate Sub-Committee that the UN's new concern about missiles helped explain the Iraqi authorities' recent obstruction of UN inspectors. On five occasions last week they refused to let UN inspectors into government buildings suspected of concealing launchers or documents related to the existence of the missiles.
Mr Ekeus's team believes that between six and 16 missiles are probably being concealed on trucks and moved between military sites in order to evade the UN inspectors. The chemical and biological warheads could be kept separately. UN inspectors would need to be delayed for an hour or so to allow the trucks carrying the missiles to escape.
It was not until last August that the UN realised Iraq might be able to build the missiles from scratch, following testimony from Saddam Hussein's fugitive brother-in-law, Hussein Kamel Hassan, the former minister for military industry, who had defected to Jordan but was killed on Saddam's orders after returning last month.
The missiles which the UN suspects the Iraqis are hiding are al-Husseins, an improvement on the original Scud, with a smaller warhead (300kg instead of 800kg) and a maximum range of 650 km (400 miles). They can carry chemical or biological warheads and, fired from Iraq could hit all of Israel, Riyadh in Saudi Arabia and Tehran. Iraq is believed to have produced at least 50 warheads filled with nerve gas and 25 filled with botulism toxin.