As millions of Americans are threatened with being dropped from their health insurance, Republicans are coming to the defense of insurance companies who they say are getting whipsawed by Obamacare regulations that are disrupting the market and leading to higher premiums.

Many consumers are already receiving notices that they will have their plans cancelled as insurers face new requirements under Obamacare.

President Obama has faced a barrage of criticism for repeatedly promising Americans that they could keep their existing health care plans if they liked them once Obamacare took effect.

But regulators have vowed to look into the cancellation notices and the White House has met with insurance companies about the rollout of the president’s signature domestic achievement.

One of the largest regional health plans in the nation, Blue Shield of California, on Tuesday said it would allow customers to stay on terminated plans until March after state regulators demanded it, the Wall Street Journal reported.

The same day, White House Chief of Staff Denis McDonough met with top executives from large insurers and discussed the cancellation notices, along with ongoing technical problems with that have led to fewer healthy, young people signing up for plans.

Democratic Sens. Mary Landrieu, D-La., and Joe Manchin, D-W. Va., have introduced a bill that would lift some of the Obamacare requirements on previously offered plans – a tweak to the law they believe will prevent some plan cancellations.

But Sen. Richard Burr, R-N.C., puts the blame for the cancellations squarely on administration officials who wrote regulations he says they knew would lead insurers to drop some products and offer other plans.

“I think it was totally disingenuous on the part of the administration to construct the law in a way that they knew what the outcome was, they facilitated what the outcome was and they totally misled” the American people, he told the Washington Examiner on Wednesday after questioning Health and Human Services Secretary Kathleen Sebelius at a Senate Finance Committee hearing.

Burr also said an administration tweak to the law that extended the March 31 deadline for people to get health insurance gives insurance companies no chance to assess their current pool of customers and would inevitably push premiums higher for 2015 because the companies would be trying to manage their risks.

When the administration made the decision to adjust the deadline to March 31, Burr said “they forgot” there was a requirement — starting April 1 — for insurers to submit their plans for premium charges for 2015.

“So in essence, [insurers are] going to have no insurance experience with the pools because the pools may have just been established on March 31,” he said. “That means the 2015 premiums will be grossly inflated to accommodate what they don't know.”

During Sebelius' Wednesday testimony, Sen. Rob Portman, R-Ohio, asked whether she could tell him how many Ohioans had their insurance plans cancelled and whether the administration was keeping track of those numbers.

“That's proprietary insurance information,” Sebelius said. “I do not know.”

Afterward, Portman said he he was surprised that HHS was not tracking that type of information.

“[She told me] you have to call the insurance companies,” he said. “A lot of states are providing that data and most of my colleagues know it. So she's not interested in getting information from insurance companies on what's happening in different states. That concerns me.”

Democrats, however, say concern for the insurance companies’ bottom line is completely misguided.

Sen. Jay Rockefeller, D-W. Va., a senior member of the Finance Committee, said insurance companies are using any excuse to drop coverage and need more regulations to force them to retain consumers.

“I'm chairman of the Commerce Committee and I spent two years dealing with the insurance companies doing nothing but canceling plans as fast as they could using any excuse – sometimes not even offering an excuse,” he said, noting one case in which an insurer canceled a policy on a 10-year-old child dying with cancer because he had run up against his lifetime limit.

“I think insurance companies should do what they're meant to do – and they don't,” he added.