The three men, shackled in leg irons and handcuffed, were brought to court under heavy police guard.

The court ordered that the men, Jona Dixon, Gary Blanchard, and Joseph Pettijohn, be remanded in custody until 26 March.

Joe Winter in Harare: The men refuse to say what the weapons were for

They are accused of trying to sabotage the operations of Zimbabwe and the Democratic Republic of Congo in their ongoing fight against rebels trying to oust Congolese President, Laurent Kabila.

'Assaulted in custody'

The Americans were arrested at Harare airport last weekend, when they were found to be carrying arms.

Lawyer Jeremy Callow: Serious allegations against the police

They say they were assaulted and subjected to other inhumane treatment while in custody.

Their lawyer said he was hoping for an independent medical examination of the three men on Sunday, after the court had ordered an examination by a prison doctor on Saturday.

Zimbabwean officials have long maintained that the United States is backing the rebellion against Laurent Kabila through the proxies of Uganda and Rwanda.

Although the US embassy in Harare has denied having any links to the three men, the arrest could be seen as justifying Zimbabwe's fears.

Carrying arms

The trio are accused of trying to sabotage Zimbabwe's fight against Congolese rebels

The men, who say they are missionaries, were detained last Sunday when one of them tried to take a gun on board a plane at Harare airport.

Further searches turned up around 30 pistols, sniper rifles and sub-machine guns hidden in their bags and in a truck parked nearby.

Since the arrest, Zimbabwe's authorities have remained silent, refusing even to release their names while investigations continue.

'Military saboteurs'

Police commissioner Augustine Chihuri told a news conference that the men were highly trained military saboteurs on a mission to commit acts of terrorism, espionage and sabotage in both Zimbabwe and Congo.

He said they had been spying on the military operations of the forces fighting the Congolese rebels and that they would be charged on Saturday.

It comes a day after a US and five British diplomats were expelled from Congo for spying and just over a week after Western tourists were killed in Uganda in revenge for alleged British and American support for Uganda's president, Yoweri Museveni.