Yemeni security forces have detained more than 40 supporters of Shaikh Husain Badr al-Din al-Huthi - a Zaidi Shia leader who the government accuses of inciting anti-US hatred during Friday sermons, an Aljazeera correspondent in Yemen reported.

A Yemeni security source vowed to continue pursuing and apprehending al-Huthi and his supporters for allegedly inciting violence and spreading anti-US sentiments in the governorate of Saada, 240km north of the capital Sanaa.

"We will besiege al-Huthi and his supporters and force them to surrender."

Witnesses reported the Yemeni government's use of helicopters to hunt al-Huthi supporters in the Hidane region of Saada.

Casualties were reported in several clashes, the Aljazeera correspondent said, but no figures were yet available.

Week-long fighting

The detaining of 40 supporters caps a week that has seen at least 13 killed in clashes between al-Huthi's supporters and government forces.

Seven of those killed were government soldiers, a government spokesperson said.