"While we don't yet know the immigration status of the people who have terrorized the communities in Massachusetts, when we find out, it will help shed light on the weaknesses of our system," he added. "How can individuals evade authorities and plan such attacks on our soil? ... How do we ensure that people who wish to do us harm are not eligible for benefits under the immigration laws, including this new bill before us?"
The bombing suspects two brothers, one of whom was killed in a police shootout Thursday night and one who was captured Friday night moved to America some five years ago and have been students in the Boston area, news reports say.
Sen. Chuck Schumer, a New York Democrat who was part of the Gang of Eight that drafted the new immigration legislation, urged caution as information is released about the suspects.
"I'd like to ask that all of us not jump to conclusions regarding the events in Boston," Schumer said, "or try to conflate those events with this legislation."
Homeland Security Secretary Janet Napolitano was expected to testify Friday before the committee and take tough questions from immigration-reform opponents but canceled shortly before her appearance to help oversee the Boston manhunt and investigation.
Sen. Orrin Hatch, R-Utah, who helped write some of the bill's language on farmworkers, said he wants to support the underlying legislation but still has many questions about its details.
His Utah GOP colleague, Sen. Mike Lee, said the complicated system can't be fixed "overnight" and instead argued it should be done in stages over "several years."
"I'm wary of trying to do this in one fell swoop," Lee said. "Good policy rarely flows from massive bills that seek to fix every problem in a single, sweeping piece of legislation."
Judiciary Chairman Patrick Leahy, D-Vt., argued in an earlier hearing that those who want to slow down the process are really trying to kill meaningful reform.
"Despite all our efforts and all our progress, there are some stuck in the past who are repeating the demands of enforcement first. I fear that they mean enforcement only," Leahy said in February.
"To them, I say this has stalled immigration reform for far too long. We've effectively done enforcement first and enforcement only. It's time to proceed to comprehensive action to bring families out of the shadows."
The Judiciary Committee will hold a second hearing Monday on the legislation, though it's unclear if Napolitano will appear then.