Political tensions were running high in Yemen Friday following the return of President Ali Abdullah Saleh from months of medical treatment abroad.

There are reports of sporadic gunfire, explosions and military vehicles roaming the streets as supporters and opponents of Mr. Saleh prepared to gather after Friday's prayers.

The embattled president arrived in Yemen from Saudi Arabia, where he spent three months recovering from injuries sustained in an attack on his presidential compound in Sana'a.

Supporters of Mr. Saleh honked their car horns and shouted slogans after his arrival in the Yemeni capital around dawn Friday. Hours after returning, he called for a truce and talks to end his country's political crisis. Mr. Saleh has not abided by previous agreements for him to leave office.

In recent days, Yemen's political parties said they were working on a plan to force Mr. Saleh out of power.

Earlier this week, representatives of the six-nation Gulf Cooperation Council met with Vice President Abed Rabbo Mansour Hadi in Sana'a in an attempt to revive a long-stalled plan that calls for President Saleh to hand over power to a deputy.

The U.S. White House on Friday urged Mr. Saleh to begin a “full transfer of power.”

In his statement after returning, Mr. Saleh said that the solution to Yemen's mounting anti-government unrest was dialogue — not “guns and cannons.” He urged government and opposition forces to observe a truce and ceasefire.

Protests against Mr. Saleh have escalated over the past week. Clashes between pro- and anti-government forces have left nearly 100 people dead.