Egypt's prime minister-designate vowed Friday before thousands of demonstrators at a central Cairo square to do everything he could to meet their demands for political change and pleaded with them to turn their attention to "rebuilding" the country.

Meanwhile, the Supreme Armed Forces Council that took control of the country from ousted President Hosni Mubarak said a referendum on constitutional changes to allow for competitive parliamentary and presidential elections will be held on March 19.

The new prime minister, Essam Sharaf, was picked by Egypt's military rulers on Thursday to replace Ahmad Shafiq. Shafiq was the last premier to be named by Mubarak, and his resignation was among the major opposition demands.

A former transport minister, Sharaf endeared himself to the protesters when he joined the demonstrations that forced Mubarak to resign on Feb. 11. He made his address Friday at Tahrir Square, the protests' epicenter.

"I draw will and determination from here," he told the estimated 10,000 demonstrators. "I will do my utmost to realize your demands," he said, pledging to step down if he fails.

Sharaf, a U.S.-educated civil engineer, served in the Cabinet for 18 months between 2004 and 2005.

His appearance at the square on Friday — he was carried on the shoulders of demonstrators to and from the podium — was the latest evidence of the power retained by youth groups nearly a month after they ousted Mubarak. Sharaf's government will serve in a caretaker capacity until elections are held.

However, Sharaf declined to take an oath of office before the demonstrators as they demanded and left the square amid chants of "Swear! Swear!" He is to be officially sworn in by the military after he forms his Cabinet.