© Greg Nash Senators press Pence over coronavirus response in private briefing

Senators on Tuesday pressed Vice President Pence in a closed-door meeting over the administration's response to coronavirus, particularly expressing concerns with a lack of testing.

Democratic senators, in particular, asked sharp questions of Pence and administration health officials during a visit to their lunch meeting to discuss the spreading virus.

Some Republican senators, in addition, said they shared growing concerns among Democrats and experts that there are not enough tests being made available, hindering the ability of officials to know how widespread the virus is within the United States.

FDA Commissioner Stephen Hahn told GOP senators, repeating his public comments, that up to a million tests will be available by the end of the week. But some senators, as well as some public health experts, have expressed skepticism of that total.

In the Democratic lunch, Sens. Patty Murray and Maria Cantwell, who represent Washington state, which is at the center of the spread of the virus in the U.S., took a lead role in questioning Pence.

Cantwell asked the vice president, who President Trump tapped to lead the administration's response, about the lack of tests available.

"They keep throwing out numbers like millions of tests and we're saying, 'that's not right,'" Cantwell told reporters afterward. "Millions of tests aren't available right this second. People are calling their doctors and they're not being able to get tests."

Pence responded by saying that the FDA took steps over the weekend to allow academic and commercial labs to test, expanding the sources of testing, Cantwell said.

The administration has faced criticism for a slow effort to ramp up testing, including problems that plagued the tests and meant some of them did not work, as well initially imposing strict criteria on who could get testing.

Those criteria have now been loosened and officials say more tests are being sent out.

"They're scrambling," said Sen. Debbie Stabenow (D-Mich.), adding that Pence said he "realized that was a concern" when asked about lack of testing.

Sen. Bill Cassidy (R-La.) said that there was "a lot of concern about the testing" among Republican senators as well.

"Our capacity is not where it needs to be right now," added Sen. Marco Rubio (R-Fla.), though he noted that officials are ramping up their efforts on testing.

Experts say the virus could have been circulating in the United States for weeks undetected because a lack of tests meant it simply was not discovered.

Senators said that worried constituents, particularly in Washington State, have been trying to get tested but are being met with confusion and lack of clear answers.

"They didn't have the answers we needed," Senate Minority Leader Charles Schumer (N.Y.) told reporters after the meeting. "The biggest question: testing. When and where? They could not answer how soon people would be able to get the tests."

"We need to know where people can get it, how people can get it and we need to make sure it's not so costly that people don't get it," Schumer added. "And there were no answers to those vital questions."

Democratic senators also raised concerns that Trump has publicly downplayed the threat in a misleading way.

"The administration on a whole has denied this is happening," said Sen. Jon Tester (D-Mont.). "There's not enough test kits, we don't know how wide it is because the president dropped the ball early."

Nathaniel Weixel, Jessie Hellmann and Jordain Carney contributed.