Two rhinos are in a critical condition after they were dehorned in an attack in South Africa as poaching moves southwards in the country, a game reserve spokesman said Monday.

"Both the rhinos' horns, the long and short horns, were hacked off with a machete," said Pieter de Jager, spokesman for the Fairy Glen Private Game Reserve in Worcester, near Cape Town.

A bull and pregnant cow were darted with M99, a morphine, and dehorned early Sunday morning. Two darts were found in the cow's left side and have been sent for forensic tests.

"The horns were hacked out so deeply that the rhino's airwaves were damaged," De Jager told AFP.

The foetus might abort as its mother battled the drug overdose.

Poachers have killed a record 405 rhinoceros in South Africa since the start of the year, South Africa's national park board said last week.

Rhino killings have spiked from 13 in 2007 as poachers hunt for rhino horn, made of the same substance as human fingernails.

It is popular for use in Asian medicinal treatments -- especially in China and Vietnam, where it is believed to cure cancer despite scientific evidence to the contrary.

South Africa's army has been called in to police the Kruger National Park in the north, but authorities have struggled to stop poaching syndicates that use helicopters, night vision equipment and high-powered rifles to hunt their prey.

It now seems poaching has reached the country's south.

"It has very recently started moving down to the Western Cape province," said De Jager.

The province had just over 30 rhinos. More than 80% of Africa's rhino population are found in South Africa.