Authorities offered last week six conditions for halting the massive military attack against the rebels in Saada, some 240 km northwest of Sana'a.

The conditions included the rebels' withdrawal from all districts of Saada and mountainous sites and giving up military hardware they have seized from the army, the official Saba news agency said.

Also among the conditions was a call for the rebels to clarify the fate of a German family of five and a British engineer taken hostage in Saada in June.

The six people were among a group of foreign hostages - seven Germans, a Briton and a South Korean. They were abducted by armed men in Saada, where the rebels operate.

Three of them, two German women and a South Korean female teacher, were found dead two days after the abduction.

The rebel leader Abdul-Malik al-Houthi has rejected the six conditions mentioned by the authorities.

Scores of insurgents and civilians have been killed since the army began its onslaught on strongholds of the Houthi rebel group on the border with Saudi Arabia Aug 11.

The offensive included aerial, artillery and missile strikes on strongholds of the rebels in strategic heights overlooking the borders with Saudi Arabia.