ALGIERS — Tens of thousands of Algerians packed the streets of the capital on Friday in the largest protest yet against the rule of President Abdelaziz Bouteflika, a clear sign that they had rejected as insufficient his offer not to seek a fifth term as president.

“This wasn’t even a proposal,” said Chafika Kherici, a 42-year-old chemist who was there with her sister and nephew, along with thousands of others in front of the city’s historic main post office. “Nobody is satisfied with it. We want to be free, and we want the government to leave.”

“Anyway it’s not even a government, it’s a clan,” said Ms. Kherici.

For a fourth straight week, the crowd chanted over and over that Mr. Bouteflika’s time was up. They had filled the streets even before the end of Friday prayers, the most important of the week. The protesters said they were determined to carry on with what many called a revolution — a noisy, festive one with singing, chanting, drumming and shouting.