They were the largest protests since President Ali Abdullah Saleh came to Riyadh for medical treatment for injuries suffered in an attack on his compound. Some of Saleh’s family and closest aides remained behind, and Yemen remains locked in a power struggle between the president’s allies and tribesmen demanding an end to the regime’s nearly 33-year rule.

In Washington, the State Department’s counterterror coordinator said the US is worried that the ongoing unrest in Yemen could fuel connections between Al-Qaeda-linked militants there and Al-Shabab insurgents in Somalia.

The American official, Daniel Benjamin said insurgents in Yemen are trying to take advantage of the turmoil in their country, are operating more in the open and have been able to acquire and hold more territory.

Residents in Shabwa, one of the Al-Qaeda strongholds in southern Yemen, are reporting intensifying overflights by US drones, suggesting the Americans are keeping close watch on the situation.

On Tuesday, tens of thousands of young people crowded outside the home of acting president Abed Rabbo Mansour Hadi, who assumed power when Saleh left. The crowd vowed to stay outside Hadi’s home — which is protected by special forces led by Saleh’s son — until their demands were met.

Many in Saleh’s inner circle remain in positions of power, including his son Ahmed, who commands the special forces and Yemen’s Republican Guard. Hadi's role in the power struggle is unclear, but he has met with the opposition, suggesting he’s willing to exercise some constitutional authority.

A senior Yemeni official in Riyadh said Saleh had developed a problem with his throat, but would not elaborate beyond describing the president’s condition as “tragic.”