Washington (CNN) -- The man arrested on suspicion of attempting a car bomb attack on New York City's Times Square has waived his right to a speedy court appearance, the head of the Senate Intelligence Committee said Tuesday.
Sen. Dianne Feinstein, D-California, told reporters after a classified briefing on the case that Faisal Shahzad waived his right to a speedy arraignment after his May 3 arrest on terrorism charges.
"That, of course, suggests he's continuing to provide valuable information to authorities," Feinstein said.
However, she and Sen. Christopher "Kit" Bond of Missouri, the ranking Republican on the panel, disagreed over whether information provided in the briefing proved that the Pakistani Taliban had a role in the attempted attack.
On Sunday, Attorney General Eric Holder said on morning talk shows that the Pakistani Taliban, also known as Tehrik-e-Taliban or TTP, had directed the bombing plot and may have provided money for it. Other U.S. officials also have said TTP was involved in the plot.
Bond said he heard nothing in the classified briefing to substantiate the connection announced by Holder. Shahzad may have claimed such connections, Bond said, but there was no independent confirmation so far.
"The definitive statements I heard Sunday I believe have not been confirmed," Bond said, adding that connections to TTP "have not yet, I believe, been confirmed by other sources."
Feinstein responded by saying she disagreed with Bond on that point, but added, "That shouldn't be debated here."
The briefing came eight days after Shahzad, a 30-year-old Pakistani-American, was arrested after a vehicle filled with explosive materials was left in Manhattan's Times Square on May 1. The makeshift bomb failed to detonate, preventing what could have been a deadly attack in one of the nation's busiest areas.
Shahzad, who is detained by federal authorities, has not yet appeared in court.
Both Feinstein and Bond complained at the delay in getting briefed by officials from the FBI, the Joint Terrorism Task Force and the Department of Homeland Security.
In addition, Feinstein called for tighter screening of international travelers and stronger controls over money transfers to try to screen what she called a new kind of terrorism threat.
"In this case, Shahzad was almost completely under the radar, which in many ways is even more ominous," Feinstein said. "... It's clear we're facing a new kind of attacker who is already here able to hide in plain sight, and we need to think about new defenses."
She called for more rigorous screening with federal no-fly lists, even though that could bring false identifications.
"There's a certain amount of this that we're going to have to put up with as a nation," Feinstein said of what she called the "occasional mismatch" of names on the no-fly list with the wrong people.
After Shahzad was arrested minutes before the flight he had boarded at New York's John F. Kennedy International Airport was set to depart, the government ordered airlines to check their passenger lists against the no-fly list every two hours instead of once every 24 hours.
Feinstein said Tuesday the new guideline is insufficient. A check should be required every 30 minutes, she said.
A senior administration official told CNN Monday that when Shahzad last traveled to Pakistan, he was looking for help from the Pakistani Taliban in carrying out a bomb attack.
"The question is: Did he go there looking for help or did he fall in their lap? It seems the former. It appears he went seeking help for this attack," the official said. "He had an attack in mind when he went there."
The official spoke on the condition of anonymity because this person wasn't allowed to speak publicly about the investigation.
CNN's Elise Labott, Alan Silverleib and Tom Cohen contributed to this report.