"The incident was politically motivated. There are people who want to take over the government before the 2012 general election," said Metsing on state radio. One of the suspects in the shooting was killed and two arrested in clashes with security forces, said the minister, a Reuters report said.

South African President Kgalema Motlanthe, who also chairs regional, grouping SADC, described the attack as heinous.

"SADC condemns any attempt at unconstitutional transfer of power. Such acts have no place in our region," he said in a statement. He said South African security forces apprehended two of the "perpetrators."

South African police officials declined comment.

Mosisili's Lesotho Congress for Democracy (LCD) scored a landslide win in a parliamentary election in February, 2007 and has ruled for 12 years but has been accused increasingly of failing to deliver on promises of economic growth and jobs.

"South Africa will pay extremely close attention to this and will assist Lesotho authorities to track down the culprits in order to ensure stability and to contain any kind of civil disorder in Lesotho," said Mark Schroeder, southern Africa analyst at Stratfor global intelligence company.

"South Africa is always concerned about civil disorder in Lesotho not only for what may spill over into South Africa but for disorder that may disrupt crucial supplies of water and electricity from Lesotho to South Africa."

Lesotho's fortunes have waned in recent years, particularly after a new global textile deal in 2005 removed quotas supporting an industry once seen as the kingdom's future.