This post has been updated.

The surviving suspect in the Boston Marathon bombings should not be treated as an enemy combatant, Senate Intelligence Committee Chair Dianne Feinstein (D-Calif.) said Sunday morning.

"I do not believe under the military commission law that he is eligible for that. It would be unconstitutional to do that," Feinstein said on "Fox News Sunday."

Dzhokhar Tsarnaev, the sole surviving suspect in last Monday's bombings, was taken into custody Friday. Federal officials said they plan to use a public safety exception to delay reading Tsarnaev his “Miranda” rights. But some Republican lawmakers want authorities to take further steps to classify him as an "enemy combatant," who could be charged under the laws of war in a military commission or held indefinitely without charge as a prisoner or detainee of war.

Rep. Peter King (R-N.Y.), one of four congressional Republicans who on Saturday urged the Obama administration to to treat Tsarnaev as an enemy combatant, explained his view Sunday.

"The reason for it is there are so many questions unanswered. There are so many potential links to terrorism here. Also, the battlefield is now in the United States, so I believe he is an enemy combatant," King, a senior member of the House Intelligence Committee, said on "Fox News Sunday."

Both King and Sen. Lindsey Graham (R-S.C.) agreed that Tsarnaev should be tried in a civilian court, but that he should still be treated as an enemy combatant for purposes of leaning more about possible links to terrorism.

Sens. Charles E. Schumer (D-N.Y.) aligned himself Sunday with Feinstein and Senate Armed Services Chairman Carl Levin (D-Mich.) in arguing against "enemy combatant" status. So did Sen. Dick Durbin (D-Ill.), the upper chamber's second-ranking Democrat.

"I don't think we have to cross the line and say he should be an enemy combatant," said Schumer, the Senate's third-ranking Democrat, on CNN's "State of The Union."

"Some have suggested that the apprehended suspect should be held as an enemy combatant under the law of war. I am not aware of any legal basis at this point for such a designation in this case," Levin said in a Saturday statement.

Feinstein said she believes there will be a "great deal of evidence put together" in order to convict Tsarnaev, and "it should likely be a death penalty case under federal law."