Yemen's opposition movement vowed on Sunday to intensify protests against the regime of President Ali Abdullah Saleh, after the embattled leader refused to resign by the end of the year. With violence gripping the strategic US ally on multiple fronts, the United States and Britain advised citizens to consider leaving the Arabian peninsula nation and warned against all but essential travel.
Mohammed Sabri, a leading member of the opposition Common Forum, vowed to step up anti-government demonstrations which have left at least 19 people dead since February 16, according to an AFP toll.
"We have called upon the people to widen demonstrations and escalate the peaceful struggle in all regions until he (Saleh) is left with one option, that is to leave," he said.
The ultimatum came a day after the president - who has ruled the impoverished, deeply tribal nation since 1978 - dismissed opposition calls for his resignation by the end of the year and vowed to stay on until 2013.
In a statement carried late Saturday on the state-run Saba news agency, an official close to the president said an opposition transition plan envisaging Saleh's departure before the end of the year was "vague and contradictory".
"A peaceful transition of power cannot be done with chaos, but by having recourse to the people through elections, so that they can decide who they want to lead without acts of violence and trouble," the statement said.
In other violence, suspected al Qaeda gunmen killed four elite Republican Guard soldiers earlier Sunday as they delivered food near Marib about 170 kilometres (110 miles) east of Sanaa, an official told AFP.
In the south, a security official said al Qaeda gunmen shot and killed a colonel in the army while he was doing some shopping in Zinjibar, capital of Abyan province.
Sunday's attacks were not known to be connected to the anti-government unrest, but were a reminder of what is at stake if Saleh is ousted and a power vacuum ensues.