Susan Walsh,File, Associated Press
In this Thursday, Jan. 31, 2013 file photo, Sen. Mark Udall, D-Colo., speaks on Capitol Hill in Washington. Republicans say Udall tried to put pressure on state health officials to change the number of people who had their health insurance policies cancelled.

DENVER — Republicans are accusing Democratic U.S. Sen. Mark Udall of Colorado of trying to pressure state health officials to change the number of people who had their health insurance policies cancelled as debate escalated over the national health care overhaul.

According to emails obtained and posted on the conservative blog Complete Colorado, Jo Donlin of the Colorado Division of Insurance alerted Hickenlooper administration officials in November that Udall staffers claimed state figures were inflated for the number of Coloradans whose health insurance was canceled ahead of the new law, and he was pressuring them to change them. The policies were canceled because they didn't meet minimum requirements under the law.

"Sen. Udall says our numbers were wrong. They are not wrong. Cancellation notices affected 249,199 people. They (Udall's staff) want to trash our numbers. I'm holding strong while we get more details. Many have already done early renewals. Regardless, they received cancellation notices," Donlin said in an email to her bosses on Nov. 14.

The next day, Donlin said she got a "very hostile phone call" from Udall's deputy chief of staff again complaining about the figures.

Udall spokesman Mike Saccone said Thursday that the state figures did not reflect the fact that 96 percent of Coloradans were offered the opportunity to renew their plans. He said even though some people offered renewals were quoted significantly higher premiums, they still had the option to renew.

"That was not a cancellation. Their figures could have deterred consumers from renewing their policies," Saccone said.

In an email to Udall staffers, Donlin said Udall was correct that Coloradans affected by the cancellations were provided options and some of them chose early renewals, but many people did not and their options were limited.

The National Republican Senatorial Committee accused Udall Thursday of trying to "cook the books."

"Mark Udall repeatedly deceived Coloradans and violated their trust by making promises about ObamaCare that couldn't be delivered," committee spokesman Brook Hougesen said in a statement.

Spokesmen for the insurance division and governor's office did not immediately return phone calls or emails seeking comment.

Democrats have been bracing for tough Senate races in states once considered safe, including Colorado, because of problems with the roll out of the health care overhaul. Republicans need to pick up six seats to win the Senate.

Udall, a first-term senator, voted for the 2010 health care bill and echoed Obama's often repeated but now discredited statement that people who had health insurance before the law took effect could keep it if they were satisfied.

Udall is one of the senators being targeted by new Republican National Committee radio ads reminding voters that Obama and his allies promised Americans that they could keep their health insurance. The ads, announced this week, will run in both English and Spanish in Colorado