Sana'a, Yemen  - Scores of civilians, mostly women and children displaced by hostilities in north-western Yemen, were killed in an airstrike Wednesday in Amran province, tribal sources said.

The sources said a fighter jet shelled a gathering of people in a flat, rocky expanse in al-Adi area of the Harf Sufian district, where the army is battling Shiite rebels.

In a second raid, a war plane bombed survivors as they ran for safety in nearby farmland, the sources said.

A tribal chieftain from the neighbouring Khamir district said at least 87 people were killed and more than 40 others wounded.

"It looks that they were mistaken for gatherings of rebels," the tribal chief told the German Press Agency dpa by phone from Khamir.

Military officials contacted by dpa denied the reported casualties among civilians, saying there was no gathering of displaced people in al-Adi.

The Defence Ministry, however, blamed the rebels for "preventing citizens from leaving to the safe areas."

"The terrorists are using innocent citizens as human shields," the ministry said in an e-mailed statement that did not directly mention the airstrike.

A military source told the official Saba news agency that "several rebels were killed" as the army struck rebel gatherings in Saada province and Harf Sufian district of neighbouring Amran province.

Saada, some 240 kilometres north of Sana'a, has been the centre of fierce fighting between the rebels, known as Houthis, and government troops since the army launched a massive offensive on their strongholds on August 11.

Both sides continue claiming to have inflicted heavy casualties over the last five weeks, but none of the claims have been independently verified, with the media denied access to the restive province.

Officials said the offensive will only end when all insurgents surrender or are killed.

This is the latest flare-up in the fighting that has raged on and off since the Houthis revolt began in mid-2004.

Authorities accuse the Shiite group of seeking to restore the rule of the Zaydi royal family, which was toppled by a republican revolution in 1962 in northern Yemen.

The Houthis say they are in revolt against government corruption and the Yemeni alliance with the United States. (dpa)