In the Syrian capital, Damascus, anticipation was running high on Wednesday. Ahmed al-Shara, who led the overthrow of longtime dictator Bashar al-Assad, was expected to address the public for the first time since his rebel coalition seized power almost two months ago.

But the speech never came. Instead, a series of critically important decisions were announced in spurts on the state news agency: The coalition headed by Mr. al-Shara declared him president for a transitional period, nullified the Constitution and dissolved the legislature and army that were formed under the ousted dictatorship.

While some Syrians celebrated the announcements, others were wary about the way the decisions were made and Mr. al-Shara’s decision not to speak directly to the Syrian people.

The declarations placed control over the formation of a new state firmly in Mr. al-Shara’s hands for the foreseeable future. His coalition did not say how long this transitional period would last, and it was not immediately clear whether his appointment had broad support across a diverse range of factions outside of his coalition.

“It’s a very centralized, authoritarian, top-down approach,” said Dr. Salam Said, a Syrian researcher and former lecturer at the Free University of Berlin. “Progressive Syrians and others are really worried about their role and their participation in this new state,” she added. “They feel left behind in all of these decisions.” “They say temporary president, transitional period. But how long is this period?”