Sanaa, Yemen (CNN) -- Persian Gulf states have suspended efforts to ease embattled Yemeni President Ali Abdullah Saleh from office after the president once again balked at signing a deal with opposition leaders, the group announced early Monday.

The decision came after an emergency meeting of Gulf Cooperation Council foreign ministers, which convened late Sunday in the Saudi capital Riyadh. In a statement carried by the Saudi Press Agency, the ministers said they were dropping the deal "for lack of appropriate circumstances for agreement."

Opposition leaders signed the pact Saturday, but Saleh had said he would not go along unless the opposition re-signed the agreement in a public ceremony at his presidential palace -- which was surrounded by armed pro-government protesters. Another crowd of Saleh's supporters, similarly armed, blockaded GCC Secretary-General Abdul Latif Zayani and ambassadors from several Arab and Western countries inside the embassy of the United Arab Emirates for a brief period earlier Sunday.

In a televised address Sunday evening, Saleh warned that the country faced civil war if opposition leaders refused to agree to his conditions, and that they would be to blame.

"If they do not wise up and if they want this country to enter civil war, then they must carry the responsibility of this and carry the responsibility of the bloodshed that has ensued and will ensue if they remain hard-headed," said Saleh, who has ruled Yemen for more than three decades.

Ahmed Bahri, a member of the opposition alliance JMP, expressed disappointment that the Gulf states "did not clarify that Saleh was the reason for the proposal not being a success."

"We expected more from the GCC nations to solve the Yemen crisis," Bahri told CNN.

Yemen, a key al Qaeda battleground and U.S. ally, has been roiled by protests for most of the year amid the background of anti-government demonstrations across much of the Arab world.

The United States is "deeply disappointed" by Saleh's continued refusal to sign the GCC initiative, Secretary of State Hillary Clinton said in a statement.

"He is turning his back on his commitments and disregarding the legitimate aspirations of the Yemeni people," she said. "We urge him to immediately follow through on his repeated commitments to peacefully and orderly transfer power and ensure the legitimate will of the Yemeni people is addressed. The time for action is now."

Under the GCC plan, Saleh would have given up power to a transitional government after 30 days. But earlier this month, he said he would not leave the country to sign the deal because he feared a coup, according to a senior official of his ruling General People's Congress party.

A Yemeni government official with knowledge of the talks said the Gulf states' initiative is now frozen, "and I'm not sure how or when it will move forward."

Tribal leaders, meanwhile, put armed gunmen on Yemen's main roads in anticipation of violence.

"Yemen is lawless today, and our tribes are here to ensure that safety prevails in all circumstances," said Shaef Ali Arhabi, a tribal leader from Arhab region. Arhabi said he supports the opposition, but pro-Saleh tribesman were on the streets as well.

The pro-Saleh forces had diplomats as well as ruling party officials bottled up inside the UAE's embassy in Sanaa earlier Sunday in a protest against the GCC plan. The Western and Arab diplomats were whisked out of the embassy by car after two Yemeni government helicopters landed in the compound, Yemeni and Emirati officials said.

U.S. Ambassador Gerald Feierstein said earlier that the ambassadors of Saudi Arabia, Kuwait, Oman and the United Arab Emirates, as well as those of Britain and the European Union, were among those in the embassy at the time. Yemeni security forces were seen near the embassy but did not try to disperse the protesters, many of whom were armed with machine guns, pistols or batons, eyewitnesses told CNN.

"The GCC proposal is against the will of the Yemeni people," said Sabri Ali, a Saleh supporter. "We will stand with Saleh against the criminals in the JMP and will not accept anyone to rule us except Saleh."

Government spokesman Abdu Ganaditold CNN the protesters were "expressing their views peacefully." But a U.S. State Department official, who declined to be named speaking about a sensitive ongoing situation, said it appeared that the Yemeni government was behind the demonstration.

CNN's Jenifer Fenton, Elise Labott and Mohammed Jamjoom and journalist Hakim Almasmari contributed to this report.