President Ali Abdullah Saleh was shown addressing a group of clerics and parliamentary figures with a piece of paper he said carried a commitment from Shaikh Badr al-Din al-Huthi, leader of the Shia sect battling government forces, confirming reports of such a deal.
Government officials claim al-Huthi's group is trying to install Shia Muslim clerical rule and preaches violence against the United States and Israel. The group is not linked to al-Qaida.
Saleh talked of a "conspiracy against the republican system" with outside backing, but did not elaborate.
Fighting first broke out last year in the mountainous north of the impoverished country at the tip of the Arabian Peninsula, during which al-Huthi's son Husain was killed. A new round of clashes began in March. Saleh did not say if fighting was over.
Casualties, material loss
Interior Minister Rashad al-Alimi told the meeting a total of 525 people had died and 2708 been wounded, comprising civilians and security forces. The authorities said at least 200 rebels died last year, but have not given a figure for this year's fighting.
Planning Minister Ahmad Sufan cited direct material losses of 52 billion Yemeni riyals ($274 million).
Yemen said this week it had arrested 21 supporters of al-Huthi on suspicion of hurling grenades at troops and planning to kill officials.