By Mark Doyle in Abidjan

The human rights organisation Amnesty International has accused troops loyal to the Sierra Leone government of summary executions.

Amnesty says that the Nigerian-led troops from the intervention force Ecomog killed 22 suspected rebel sympathisers on a bridge across a lagoon in western Freetown on 13 January.

Other sources in Freetown have reported executions on this bridge, and last week I saw the bloodstains on the railings, which the sources said resulted from the killings.

Nigerian officers say quite openly that they shoot rebel suspects on sight.

One Nigerian officer told me his forces were advancing against the rebels because the Nigerian army had adopted the rebels' own tough guerrilla tactics.

The officer said, on condition of anonymity, "It takes a thief to catch a thief."

Amnesty also condemned indiscriminate aerial bombardments of densely-populated parts of Freetown by Nigerian jet fighters.

When I asked a Nigerian commander about this bombing, he replied angrily that he would use the best weapons he had to deal with the rebels.

While the Nigerians' abuses have not been widely reported, this is probably because the scale of them is less than the atrocities committed by the rebels, which are so widespread that everyone has heard of them.

According to consistent, convincing evidence and eye-witness accounts, the rebels have used civilians as human shields and mutilated people with machetes.