A local tribal leader, who spoke on condition of anonymity because he feared government reprisal, said the army launched reprisal attacks on Saturday near Saada, about 180km north of Sanaa, the Yemeni capital.
The tribal official said at least 22 people - 16 of them government forces - had been killed in battles in the region over the past week, including the five reported dead in fighting on Friday.
Earlier this month, other tribal officials reported at least 18 soldiers were killed and dozens wounded.
The fighting dates to June 2004, when rebel Shia Muslim cleric Husain Badr al-Din al-Huthi lead his forces in an uprising against the government. Al-Huthi was killed in September 2004, but his followers have continued their minority rebellion.
Tribal officials said government troops were attacking rebel hideouts near Saada on Saturday and that dozens of families had fled the region in the past two weeks.
More than 600 rebels and soldiers have died in the intermittent fighting since the rebellion began nearly two years ago.
Al-Huthi, known for his anti-US views, had been accused of sedition, forming an illegal armed group and attacking government buildings and security forces.
Government officials refused to confirm accounts of the fighting, and security forces prevented reporters from
entering the region.