Yemeni President Ali Abdullah Saleh declared an end to the government's long-running war with rebels in the north last month and the prisoner release is seen as an important step toward supporting the cease-fire.

Sanaa, which is also battling a secessionist movement in the south, has come under heavy international pressure to end the northern war and focus on fighting a resurgent Al-Qaeda, which the West fears is exploiting instability in Yemen to launch attacks in the region and beyond.

Previous truces to end the northern war, which has displaced 250,000 people, have not held and analysts are skeptical about latest cease-fire.

"(Some) 236 rebels have been freed in two batches, carrying out a cease-fire signed between the two sides in February," a security source said.

The rebels welcomed the move but said only a few dozen prisoners had been released so far and that hundreds more remained in Yemeni jails.

"The decision is a positive step, and we welcome it. But we were not officially informed and until now the (full) release has not been finished," a rebel official said. "There are a large number of prisoners. The number is around 600." The prisoner release appeared to be a reciprocal move after rebels freed at least 170 government soldiers and tribal fighters last month, shortly after Sanaa accused them of dragging their feet in implementing the truce.

The Yemen defense ministry's online newspaper said the rebel prisoners had been freed in two batches, including 161 on Monday and another 75 two weeks earlier.

Government sources said many of the freed rebels had been held without charge and that Sanaa continued to hold others whose trials were pending. Those prisoners could be released at a later date if exonerated or pardoned.