Sana'a, May 1, 2011- A deal to end the unrest in Yemen has collapsed after the veteran leader President Ali Abdullah Saleh refused to sign the agreement, officials say.
The deal, brokered by Gulf Arab states, had been due to be signed in person by the president over the weekend.
The opposition said it would consider escalating the protests calling on Mr Saleh to stand down.
Under the deal, Mr Saleh would have 30 days to gain immunity from prosecution before stepping down.
The deal was agreed a week ago by Yemen's ruling party, the General People's Congress.
But an official from the six-nation Gulf Cooperation Council (GCC), which mediated the agreement, said Mr Saleh had refused to sign it.
The Yemeni leader is said to have asked a senior aide to represent him at the signing ceremony in the Saudi capital Riyadh.
A senior opposition leader said they were considering escalating pressure on the president to step aside after three months of street protests which have left at least 145 people dead.
"We are studying the options of escalations and waiting for a US-European stance on Saleh's refusal to sign," the representative said, Reuters reports.
The US is keen to resolve the unrest in Yemen, where al-Qaeda has a well-established network.
The opposition coalition approved the deal earlier only after its leaders had received "assurances" from the GCC, the US and Europe on the transfer of power.
However, the deal drove a wedge between the opposition coalition and youths who have led demonstrations against the president across the country for months.
They accuse the politicians of breaking a promise to put Mr Saleh on trial.