The American delegates to the International Olympic Committee made a last-ditch effort yesterday to persuade two key Albany lawmakers to approve the proposed West Side stadium this week or risk jeopardizing the city’s Olympic bid.

In a letter sent to the speaker of the state Assembly, Sheldon Silver, and the majority leader of the Senate, Joseph Bruno, the delegates said failing to approve the project before the IOC releases an assessment report Monday would be a “serious risk factor for the bid.”

“It is imperative that you act by June 6, the date the IOC Evaluation Commission Report will be issued to the world’s media so that the IOC members know that the stadium project is no longer in doubt,” the letter said.

Debate about the project, a 75,000-seat domed “sports and convention center” that Mayor Bloomberg has billed as the city’s primary venue for the 2012 games, has grown even more intense in the past week as both the mayor and Governor Pataki have been courting Mr. Silver with projects for his Lower Manhattan district.

Just yesterday, Mr. Bloomberg unveiled details of an esplanade along the East River that is part of more than $800 million the city is using for downtown investments – a cause Mr. Silver, a Manhattan Democrat, has been tirelessly advocating.

Messrs. Bloomberg and Pataki have denied that the downtown investments are designed to assuage Mr. Silver’s public concern that Lower Manhattan development has been neglected as a result of the mayor’s focus on the West Side. Instead, they have stressed that the blueprints have been on the drawing board since 2002 and are just now bearing fruit.

Those on both sides of the stadium issue seized on the momentum of the approaching deadline yesterday to make their best cases for and against the stadium, which would serve as home to the New York Jets and would double as an expansion of the Jacob K. Javits Convention Center.

A group of elected officials who oppose the stadium outlined new questions yesterday, including security concerns they equated with those that have delayed the Freedom Tower. Plans for that project, which was to be built on the World Trade Center site, were ordered revised last month after the New York Police Department expressed fear that the building was too close to the road.

The mayor’s press secretary, Edward Skyler, called the stadium opponents’ Freedom Tower comparison “an 11th-hour scare tactic” and described it as “a new low.”

And the Police Department’s chief spokesman, Deputy Commissioner Paul Browne, rebuffed that assertion.

“The design characteristics of the building are excellent from a counterterrorism point of view,” he said. “We had major concerns about the Freedom Tower at the outset. That’s not the case with the stadium. To the contrary, our counterterrorism experts were reassured at the outset because of the underlying robust protection built into the design.”

On another matter, Assemblyman Richard Gottfried, a Democrat whose Manhattan district includes the stadium site, said the public deserved to see documents about the government’s plan to finance its share of the $2.2 billion stadium and to get the Jets to sign binding agreements requiring the team to pay for cost overruns.

Meanwhile, Messrs. Pataki and Bloomberg hit on the same talking points at their separate news conferences in Albany and Lower Manhattan yesterday morning. Both men told reporters that the majority of City Council members and members of the city delegations of the Legislature were behind the project.

Mr. Bloomberg also referred to the IOC letter – which was signed by delegates Anita DeFrantz, James Easton, and Robert Ctvrtlik. He said it would be “impossible” for the American delegates to lobby their counterparts from other countries to vote for New York’s bid with the stadium’s future in doubt.

“What we’ve got to do is to explain to all 116 of the IOC delegates why an Olympics here would help the Olympic movement,” the mayor said yesterday.

Mr. Bloomberg said he was confident that Messrs. Silver and Bruno, whose proxies on the little-known Public Authorities Control Board must unanimously approve the $300 million in state funds for the stadium, would ultimately favor the project.

“I’m still sure that when they sit down and finally take a look at what we’re proposing they are going to say ‘This is in the best interest of New York City, New York state, and America,” Mr. Bloomberg said.

Though the PACB vote has already been postponed twice, Mr. Pataki said yesterday that vote would happen this week.

With a state Supreme Court judge scheduled to rule tomorrow on several pending lawsuits against the stadium, the vote, Mr. Pataki said, would “most likely” take place Friday, leaving more than month before the IOC announces its selection for the 2012 host city on July 6.

And what if Mr. Silver boycotts the meeting? “I don’t think that will be the case,” Mr. Pataki said. “I’m not going to hypothesize on what is or is not going to happen at the meeting, but to me there is just overwhelming bipartisan recognition that this is great for New York.”

Nonetheless, not everyone buys that argument. Opponents characterized the process as being shrouded in secrecy. Mr. Gottfried said the mayor and governor were trying to create “the illusion” of transparency.

“The truth is that they’re asking us to commit over $1 billion in taxpayer money, and if this were your money, and in fact it is, I think there are some basic things you would want us to know about this project that we do not know,” the assemblyman said.

Meanwhile, a news report yesterday suggested that Mr. Bruno might back the stadium. But spokesmen for him and for Mr. Silver said they had nothing to add to the lawmakers’ previous statements. It is unclear whether either of the men will cooperate with Friday’s planned vote.