OAKLAND -- The development team working to build a new Raiders football stadium has urged city officials to reject a lease extension for the Oakland A's because it would frustrate the football team's desire to tear down O.co Coliseum next year.

In a letter to Mayor Jean Quan and council members last week, the development team's attorney wrote that "the current proposal ... simply allows the A's to buy more time to find a site outside of Oakland ... and disrupt the ability to deliver a stadium for the Raiders and the ancillary developments adjacent to that stadium."

More than 3,000 scouts parade around the field during Scout Day at O.co Coliseum in Oakland, Calif., on Sunday, June 1, 2014. Oakland defeats Los Angeles
More than 3,000 scouts parade around the field during Scout Day at O.co Coliseum in Oakland, Calif., on Sunday, June 1, 2014. Oakland defeats Los Angeles 6-3 to sweep the series. (Jose Carlos Fajardo/Bay Area News Group) ( JOSE CARLOS FAJARDO )

The attorney, Zach Wasserman, said Tuesday that his clients who are spearheading the multimillion Coliseum City project still hoped their concerns will be addressed in the final lease deal. But it appears that several council members are frustrated with the development team and don't view their concerns as deal breakers.

Opposition from the development team, which has already spent more than $4 million in public funds, comes as council members are still debating whether to approve a lease deal with the A's that could keep the team at the Coliseum through 2024.

Councilman Larry Reid said he walked out of a private council meeting on Monday in frustration that his colleagues, some of whom think the deal is financially generous to the A's, weren't ready to vote on it in public. Another closed-door meeting to discuss a financial analysis of the lease deal will be scheduled for later this week, Councilman Noel Gallo said.

While council members and the development team say they want to keep both the A's and Raiders in Oakland, Wasserman's letter underscores the challenge in satisfying both teams. The Raiders have pinned their hopes to building a new stadium by partnering with developers on the Coliseum City project, which aims to transform the Coliseum complex into a sports and entertainment center.

But A's co-owner Lew Wolff has said that if his team decides to build a ballpark at the site, it would want to be in charge of the development.

Because outdoor sports stadiums are often money losers and Oakland can't afford to help pay for them, any new stadium development in the city is expected to include shops, a hotel and offices to subsidize the project. Sports economists have questioned whether the A's and Raiders would want to work together because a second stadium would remove land that could be used for more profitable development.

"The probability of Coliseum City working financially and some team committing to it would be greater if there was only one team involved," Stanford University Economics Professor Emeritus Roger Noll said when asked about the development in April.

The development team, which includes real estate titan Colony Capital, is concerned by a clause in the proposed lease that wouldn't force the A's to vacate the Coliseum for a Raiders stadium development until after the 2016 baseball season.

Wasserman wrote that the Raiders plan to have a new stadium built in time for the 2018 season and play elsewhere while it is being built.

"It will be critical to demolish the existing stadium in 2015 not only to construct the new multiuse Raiders' facility but also to simultaneously construct the associated developments including a hotel, retail and office buildings," he wrote.

However, several council members said this week that they have been frustrated by the lack of progress on a Raiders stadium, which still faces a roughly $500 million funding gap, and did not expect the development team's concerns to impact their vote on a lease extension.

Councilman Noel Gallo said the development team had failed to meet key benchmarks in their contract with the city, such as getting an official letter of support from the Raiders and bringing aboard a major developer. "Their performance has been below basic and we should get another group to lead that effort," he said.

The Raiders did not respond to an interview request on Tuesday.

However, in an interview with this newspaper last month, Raiders owner Mark Davis said he didn't know what he would do with his team if the A's lease deal was approved.

"There's all kinds of options." he said. "But I want to make the best one."

Contact Matthew Artz at 510-208-6435.