Republican Sen. Lisa Murkowski of Alaska said the U.S. must demonstrate a zero tolerance for aircraft entering U.S. airspace after shooting down an unidentified craft.

"The first line of defense, again, is Alaska," Murkowski told NBC News on Friday.

US MILITARY SHOOTS DOWN 'OBJECT' FLYING IN TERRITORIAL WATERS OVER ALASKA

A photo of Lisa Murkowski during a committee hearing

Sen. Lisa Murkowski, R-Alaska, questions Environmental Protection Agency administrator Michael Regan during the Senate Appropriations Subcommittee on Interior, Environment and Related Agencies Subcommittee hearing on the proposed budget for FY2023 for the Environmental Protection Agency on Wednesday, May 18, 2022.  (Bill Clark/CQ-Roll Call, Inc via Getty Images)

The Department of Defense shot down a "high altitude object" flying in territorial waters over Alaska on Friday.

She continued, "If it comes into Alaska airspace, if it comes over Alaska waters, we need to act. We need to send the message, and we need to be clear and unequivocal that we don’t tolerate this, period."

CHINESE SPY CRAFT PAYLOAD LOCATED OFF WATERS OF SOUTH CAROLINA, MOSTLY INTACT: US OFFICIAL

John Kirby

Coordinator for Strategic Communications at the National Security Council John Kirby speaks during a daily news briefing at the James S. Brady Press Briefing Room of the White House on February 10, 2023 in Washington, DC.  ( Alex Wong/Getty Images)

National Security Council spokesman John Kirby told the press the Pentagon had been tracking a "high-altitude object" flying at 40,000 feet over Alaskan airspace for about a day – but underlined there is no information yet to discern whether it was of Chinese or even "corporate" origin.

President Biden ordered the downing after being advised by the Pentagon. 

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FBI Special Agents process Chinese balloon material

(Washington, D.C) – FBI Special Agents assigned to the Evidence Response Team process material recovered from the High Altitude Balloon recovered off the coast of South Carolina.  The material was processed and transported to the FBI Laboratory in Quantico, Virginia. (FBI)

The unidentified "object" landed on frozen waters, and was significantly smaller than the large Chinese surveillance balloon shot down last week, according to officials.