LUSAKA, March 12: Zambia has detained two men suspected of possessing a cache of what police believe could be bomb-grade uranium, police and the men's lawyer said on Friday.

Police said they were conducting tests with scientists at the country's best-equipped laboratory to determine the potency of the uranium.

The two men were arrested by state intelligence officers at the Lusaka Stock Exchange on Feb 16, when Zambian President Levy Mwanawasa had been due to tour it, said a senior police officer.

Francis Changufu and Andrew Milambo, both Zambians, had yet to be formally charged, their lawyer said.

"They have been in custody since their arrest and we are waiting for scientists to verify whether what they were found with is uranium," Kelvin Bwalya said.

He said the pair would appear in a high court in Lusaka on Monday to seek bail, after they were denied bail by a lower court last week.

Under Zambian law, suspects should be charged within 48 hours of their arrest but Changufu and Milambo have been in police cells for more than three weeks without charge.

"They cannot be released on police bond because the case they have committed is very serious... We don't know the reasons why they had bomb-grade uranium and what they wanted to use it for," a police source said.

President Mwanawasa, who has pledged Zambia's support for US and British efforts to fight international terrorism, cancelled his trip to the exchange and sent a minister instead.

Lusaka division police chief Chendela Musonda said police were conducting laboratory tests on the substance with analysts at the University Teaching Hospital laboratory, the biggest multipurpose lab in the country.-Reuters