Yemeni President Ali Abdullah Saleh on Sunday warned against civil war ignited by the opposition, shortly after he announced his refusal to sign the Gulf-brokered deal.

Official Saba news agency reported that President Saleh refused to sign the Gulf-brokered deal after the opposition rejected going to the Republican Palace to sign it together with him.

Meanwhile, Saleh's ruling party signed the Gulf Cooperation Council (GCC)-brokered deal which proposed Saleh to leave office within a month, Saba said.

An aide to the president told Xinhua on condition of anonymity that Saleh attended the signing ceremony, in which five representatives of the ruling party inked the deal.

"I would sign the Gulf deal only if the opposition's representatives come to the Republican Palace to sign it with me at the same time, because the opposition would be our partner in the power for the next 90 days," Saleh said in a speech he delivered through the state television after his ruling party signed the deal.

In his speech, Saleh also warned against a potential civil war if the opposition continued to escalate the four-month-long street protests.

"The opposition coalition will be held responsible if they escalate street protests and drag the country into a civil war ... they will be held responsible for the blood that had been and would be shed during the previous days and in the next days," he said.

Saleh had earlier told the GCC official al-Zayani and Western and Gulf ambassadors to Yemen that "the opposition's signing inside closed room will be unacceptable, and such big deal should be held publicly," according to Saba.

On Saturday evening, the opposition unilaterally signed the deal and refused to meet Saleh's condition to go to his presidential palace to sign it again on Sunday.

Saleh has thwarted the U.S.-backed deal three times since April.

If Saleh signs the deal, he should leave office within 30 days in exchange for immunity from prosecution according to the terms of the deal, which also authorized the opposition to form a new government within seven days and arrange for holding presidential and parliamentary elections in 60 days.

Earlier the day, an official at Saleh's office told Xinhua that the "president sent a short message to visiting GCC Secretary- General Abdullatif al-Zayani, telling him his final word that he refused to sign the deal that requires his resignation within a month."

Meanwhile, the opposition spokesman Mohamed Qahtan considered the deal "null and void because the deal stipulated Saleh to sign first, but Saleh did not sign it."

Yemen celebrated Sunday the 21st anniversary of country's reunification as tension soared on the verge of bloody clashes between Saleh's thousands of armed loyalists and their rivals who packed the streets to demand an immediate end to Saleh's 33-year rule.

Also after Saleh announced his refusal, military tension escalated between the government forces and defected army in the capital Sanaa and other major provinces, according to officials from both the ruling party and the opposition.