Zimbabwe has put its army on full alert after seizing a US-registered cargo plane that the government said was carrying 64 suspected mercenaries and military gear.
The South African government said it had unconfirmed reports that some of the alleged mercenaries were its nationals.
President Robert Mugabe's government said yesterday it had impounded a Boeing 727-100 aircraft on Sunday evening at Harare International Airport "after its owners had made a false declaration of its cargo and crew".
State television footage of the plane's cargo showed sleeping bags, satellite phones, knives, bolt cutters and green camouflage uniforms but no firearms.
"We have mobilized all our security organs to get to the bottom of this case," said a government official.
The plane's origin and destination were a mystery today, with Zimbabwe government officials saying they would make details available once investigators cleared them.
No formal charges have been laid, and officials have not said if they believe Zimbabwe was the plane's final destination or a target for the suspected mercenaries.