A Nigerian Shi'ite group said on Wednesday 42 of its members were killed when security forces fired upon their protests in the capital Abuja over the previous two days.
The previous death toll as of Tuesday evening was 25 members of the Islamic Movement of Nigeria (IMN), who had marched in their hundreds to demand the government release their leader Ibrahim Zakzaky.
On Monday, the army opened fire on the marchers on the outskirts of Abuja. On Tuesday, the police shot at the protesters in the city centre.
"The death toll of yesterday's attack on our members has risen to seven as of now," said Ibrahim Musa, an IMN spokesman.
"They died as a result of the injuries they sustained yesterday. And the number of those killed on Monday at Maraba (an area on Abuja's outskirts) has also risen to 35."
Police and army spokesmen did not respond to phone calls seeking comment.
Zakzaky has been jailed since December 2015 when security forces killed hundreds in a crackdown on the group.
(With inputs from agencies.)