MOSCOW – President Putin, seeking to assuage rising public anger, promised a moderate increase in pensions and blamed federal and local officials yesterday for failing to properly implement Kremlin reforms that cut off benefits to millions of Russians.

Mr. Putin’s first public comments since the unpopular change took effect came hours after lines of police blocked hundreds of protesters from retaking a major intersection in central St. Petersburg that thousands of pensioners had occupied over the weekend, bringing traffic to a halt. Demonstrators blocked major avenues and key highways in other cities.

“The Cabinet and the regions have failed to fully implement the task we had discussed: in making such decisions, not to worsen the position of those who need the state’s help,” a somber looking Mr. Putin told Cabinet members in a partially televised session.

A law that gives retirees, the disabled, war veterans, and others cash stipends instead of benefits such as free medicine and public transportation took effect January 1, sparking the largest uproar in Mr. Putin’s five years in power.

Large protests have spread to numerous cities across Russia’s 11 time zones, including Mr. Putin’s hometown, St. Petersburg. Officials said the reform affects about 40 million of Russia’s 144 million people.

Protesters say new monthly payments of about $10 are worth much less than the benefits, forcing them to have to choose between food, transportation, and medicine.

The Kremlin has described the social reform as a long-overdue effort to streamline and modernize the economy, but many commentators predict now that Mr. Putin may respond to the crisis by firing government ministers.

Mr. Putin defended the reform, saying its general concept was right and that the state can’t afford to maintain the existing unwieldy and inefficient social-support system.

Without naming his predecessor, Boris Yeltsin, Mr. Putin blamed Mr. Yeltsin’s government for increasing the number of people eligible for social benefits in the 1990s, while lacking the funds to deliver. Wages and pensions were months and even years overdue, he said. “The situation is different now,” Mr. Putin said.

Mr. Putin supported decisions by some local officials to issue subsidized travel passes and also instructed the government to increase the average monthly pension by at least $7.14 instead of the planned $3.57 – and to do it March 1 instead of April 1.The Health and Social Development minister, Mikhail Zurabov, said pensions may be increased by $8.57.