Lesotho, an impoverished mountainous kingdom of two million people, is entirely surrounded by its powerful neighbour.

South Africa's apartheid rulers also sent troops across its borders to take part in wars elsewhere - namely in Angola and Namibia.

But since all-race elections in 1994, South Africa has kept to a policy of peaceful mediation in African conflicts.

The soldiers killed in Lesotho were the first South Africans to die in active service since apartheid ended.

Economic dependence

Lesotho is economically and politically dependent on South Africa.

Some 35% of male wage earners work over the border - many of them in the mines.

Remittances from miners working in South Africa added 33% to the GDP in 1996.

Almost all Lesotho's electricity comes from South Africa which also operates its railways, according to1996 statistics.

But the kingdom recently completed the first phase of a $4bn dam project enabling it to sell water to its neighbour.

Lesotho will eventually channel 26 cubic metres per second from its mountains to the dry industrial heartland of South Africa.

The scheme will also include a power station which will supply virtually all Lesotho's electricity meaning it no longer has to rely on its neighbour.

President Nelson Mandela, who attended the opening ceremony in January, said the project testified to a new spirit of co-operation in Africa.

Opposition parties gained just one seat in the polls

The mobilisation of South African troops caps weeks of unrest by opposition demonstrators in Lesotho who claim the May elections were rigged.

Although 12 parties and 30 independents participated in the polls Lesotho's ruling Congress for Democracy Party won 79 out of 80 of the seats.

A report by a commission of representatives from South Africa, Botswana and Zimbabwe last week cited "serious concerns" about the voting but did not call for a re-run.

South Africa's intervention follows fruitless efforts by mediators over the weekend to bring Lesotho's government and opponents together in talks.

Royal coup

But it is not the first time President Mandela has intervened.

Government troops were readied for possible mobilisation during the last serious uprisings in 1994.

In August that year King Letsie dissolved parliament and deposed the then prime minister Ntsu Mokhehle.

Mr Mokhehle was a former member of the African National Congress and supported the South African liberation movement.

President Mandela said he would not tolerate the royal coup which ''threatened the stability of all southern African states''.

Earlier that year Lesotho had asked South Africa for help following suspicions that rival army factions were trying to overthrow the administration.

Strained relations during apartheid years

During the apartheid years, the white-led government in Pretoria intervened in Lesotho on several occasions, and put constant pressure on the country over its ties with the ANC.

In 1982 it raided Maseru in search of ANC supporters killing 42 people.

Lesotho's leader Chief Leabua Jonathan forged links with the key communist powers and accepted military training from North Korea for a paramilitary group.

S.Africa considered sending troops in 1994

But Pretoria pulled the plug on his government with a blockade in January 1986 and days later installed South African-trained soldier Major General Justin Lekhanya as head of a military junta.

Maj Gen Lekhanya forced King Moshoeshoe into exile and his son Letsie was installed as a monarch without power.

Maj Gen Lekhanya was overthrown in April 1991 and Moshoeshoe allowed home.

In 1993 Lesotho, a British territory from 1868 until 1966, held its first free election since independence with Mr Mokhehle elected prime minister.

Lesotho was founded by King Moshoeshoe's great great great grandfather, Moshoeshoe I, a local leader who moved his people there in 1820 to escape the Zulu expansion bringing turmoil to much of southern Africa.