OAKLAND, Calif. — After weeks of cautiously accepting the teeming round-the-clock protests spawned by Occupy Wall Street, several cities have come to the end of their patience and others appear to be not far behind.

Here in Oakland, in a scene reminiscent of the antiwar protests of the 1960s, the police filled downtown streets with tear gas late Tuesday to stop throngs of protesters from re-entering a City Hall plaza that had been cleared of their encampment earlier in the day.

Those protests, which resulted in more than 100 arrests and at least one life-threatening injury, had appeared ready to ignite again on Wednesday night as supporters of the Occupy movement promised to retake the square, where the encampment site was fenced off.