Franken campaign attorney Marc Elias said the missing Minneapolis ballots absolutely must be found and tallied in the recount.
"The outcome of this election might be at stake. Let me be clear -- the integrity of this election, the integrity of the Minnesota electoral process is also at stake," said Elias. "We will not stand for this. The people of Minnesota will not stand for this. Find the ballots. That's our message -- find the ballots."
Elias told reporters the precinct from which the ballots went missing is a particularly strong area for Franken, since many University of Minnesota students live there.
Elias called on the Secretary of State to oversee a massive search for the 133 ballots.
"They should conduct a systematic forensic search of the polling location, any vehicles that were used to transport those ballots or other election materials, and the warehouse where those ballots were stored," said Elias. "They ought to go through and look and catalog every envelope in that warehouse that has ballots in it."
At a late afternoon news conference, Minneapolis officials said they do believe roughly 130 ballots are missing and they expressed hope that they'll be able to find them.
They say they should all be in a sealed envelope, and that they're concentrating their search on the warehouse where the ballots are stored.
“The integrity of this election, the integrity of the Minnesota electoral process, is at stake.”Franken attorney Marc Elias
State officials have indefinitely extended the final recount deadline for the precinct where the ballots are missing. They say one option would be for the canvassing board to use the machine count tally for that precinct if the ballots are not found.
The Secretary of State's office dispatched its No. 2 official to witness the investigation.
Elias would not say what his next step will be if the ballots are not found, but he made it clear nothing is off the table.
Republican Sen. Norm Coleman's recount attorney Fritz Knaak noted he's been raising concerns about missing ballots for days.
In another recount development, Knaak told reporters the Coleman side is withdrawing challenges to 650 ballots.
Franken announced Wednesday he was withdrawing 633 of its ballot challenges. At that time, Knaak said he would not follow suit -- at least until after all of the counties finished counting ballots. Knaak says he then heard from his boss.
"I received a communication from Sen. Coleman that made it very clear that he wanted us to respond to this gesture on the part of the Franken committee, and accelerate the process, I guess is the way I'd put it," said Knaak.
Knaak says Coleman is emphatic that taxpayer and elections officials' time should not be wasted with unnecessary challenges. But Knaak conceded there are likely many more challenges his side could have have withdrawn.
Knaak says he thinks the best way to tackle the thousands of challenged ballots is for the two sides to work together and review them. Knaak says he has asked his counterpart at the Franken campaign a second time to do just that.
"Our invitation was to sit down with them early next week and actually get the job done, I hope," said Knaak. "Where we can ... sit down and just sort through as many of these as we possibly can, and ideally get the number down to the hundreds."
Franken attorney Marc Elias said he's got a process in place to withdraw his own challenges. Still, he was open to accepting Knaak's invitation.
"If it is easier to anyone in this process to have a meeting, then we'll have a meeting," he said.
Elias declined to say when he would meet with the Coleman side.
Both campaigns have been aggressively fundraising since the election to pay for their recount operations.
According to documents filed with the Federal Election Commission, in the three weeks following the election Coleman took in more than $1.8 million and had more than $2.1 million cash on hand on Nov. 24 -- the last day of the latest reporting period.
Al Franken's campaign said it also raised $2.1 million for it's recount effort, both directly through the campaign and by a joint fundraising committee.