PARIS, France — A nationwide strike by major French unions canceled flights and trains and shut the Eiffel Tower yesterday, disrupting daily life for many and putting new pressure on the government to drop a plan to raise the retirement age by two years.

Unionized train and Paris public transport workers vowed to stay off the job for at least another day, and police said at least 1.2 million people marched in protests against the plan, the largest turnout in four nationwide demonstrations over the last five weeks.

That could be a signal of rising momentum for the movement facing off against President Nicolas Sarkozy’s governing conservatives over its proposal to raise the retirement age from 60 to 62.

The government has refused to back down, saying the plan is the only way to save the money-draining pension system. Some unions upped the ante by declaring open-ended strikes starting Tuesday, meaning walkouts could drag on for days or even weeks.

The outlook for Wednesday was still uncertain in many sectors, but many workers at the national railways planned to stay off the job, as did some employees of the Paris transport network. Some oil workers pledged to keep up a protest at refineries, and one union warned of looming gasoline shortages.

On Tuesday, hundreds of tourists visiting the Eiffel Tower were ushered away after workers there voted to join the strike.

“The closure of the monument is a symbol,” said Yann Leloir, a striking employee. The tower — France’s most-visited monument — is to reopen Wednesday as usual.

Unions fear the erosion of a cherished workplace benefit, and say the cost-cutting ax is coming down too hard on workers.

Despite the strikes, parliament has pushed ahead with the reform: The lower house approved it last month, and the Senate has already approved the article on raising the retirement age to 62 but is still debating the overall reform.

Even with the change, France would still have among the lowest retirement ages in the developed world. The country has a huge budget deficit and sluggish growth, and the government says it must get its finances in better order.

France’s European Union partners are keeping watch as they face their own budget cutbacks and debt woes. Sarkozy’s government is all but staking its chances for victory in presidential and legislative elections in 2012 on the pension reform, which the president has called the last major goal of his term.

Prime Minister Francois Fillon told lawmakers that backing down would be “economic madness and a social catastrophe.”

Meanwhile, more than 200 street demonstrations were held throughout the country, with workers marching amid smoke from flares and holding aloft giant union balloons.

Some 1.23 million people marched in boisterous but peaceful protests across the country, the Interior Ministry said, though the CFDT union put the total turnout at 3.5 million. Both figures were higher than the estimates from other marches over the last five weeks.

Some high school students took part, saying they feared for their future. In Paris, high schoolers from suburban Vitry-sur-Seine carried a cardboard coffin above their heads in a mock funeral procession.

“It’s Sarkozy’s tomb,” said 17-year-old Roxanne Evenisse.

Another marcher said he doubted the protest would move France’s leaders.

“They are deaf,” said Jean Baillon, 57, an employee of France’s nuclear energy agency, CEA. “But if this lasts a few more days, then maybe that will change.”

Bernard Thibault, head of the CGT labor union, told i-Tele news channel that this time the strikes “will continue for as long as needed.” Past walkouts on the issue lasted only one day.

Train drivers launched an open-ended strike Monday night, and the work stoppages widened to other e high-speed trains were running, while Eurostar service to Britain was unaffected, the SNCF rail networks said.

Around 30 percent of flights were canceled at France’s busiest airport, Paris’ Charles de Gaulle, while cancellations at the capital’s second airport, Orly, reached 50 percent, according to aviation authorities. Most of the affected flights were short-haul domestic flights or inter-European flights.

Workers at all six of oil giant Total SA’s French refineries were striking, and two of them had begun preparations for total shutdowns, company spokesman Michael Crochet-Vourey said. He declined to estimate how long it would take before the strikes translated into gas shortages at the pump.

Participation in the strikes varied by sector. Nearly 17 percent of postal workers stayed off the job, the national mail service said. The Education Ministry said about 22 percent of teachers took part, less than during the last strike Sept. 23.

With service on suburban trains and the Paris subway and bus lines slashed by about half, commuters rolled into work on bikes, rollerblades and skateboards.

“I understand the strikers, I tolerate it,” said Fuad Fazlic, 38, a tailor at French luxury label Chanel, as he rolled his bicycle out of the Gare du Nord train station on his way to work.

Fazlic said he learned his lesson after strikes in 1995 brought much of France to a standstill for about two months: “I have been biking to work ever since.”