WASHINGTON (AP) - Republicans said Sunday that the Internal Revenue Service's heightened scrutiny of conservative political groups was "chilling" and further eroded public trust in government. Lawmakers said President Barack Obama personally should apologize for targeting tea party organizations and they challenged the tax agency's blaming of low-level workers. "I just don't buy that this was a couple of rogue IRS employees," said Sen. Susan Collins, R-Maine. After all, groups with 'progressive' in their names were not targeted similarly. If it were just a small number of employees, she said, "then you would think that the high-level IRS supervisors would have rushed to make this public, fired the employees involved, apologized to the American people and informed Congress. None of that happened in a timely way. The IRS said Friday that it was sorry for what it called the "inappropriate" targeting of the conservative groups during the 2012 election to see if they were violating their tax-exempt status. But according to a draft of a watchdog's report obtained Saturday by The Associated Press that seemingly contradicts public statements by the IRS commissioner, senior IRS officials knew agents were targeting tea party groups as early as 2011. Lois G. Lerner, who heads the IRS division that oversees tax-exempt organizations, said last week that the practice was initiated by low-level workers in Cincinnati and was not motivated by political bias. But on June 29, 2011, Lerner learned at a meeting that groups were being targeted, according to the watchdog's report. The 9/12 Project is a group started by conservative TV personality Glenn Beck. Rep. Mike Rogers, R-Mich., said "the conclusion that the IRS came to is that they did have agents who were engaged in intimidation of political groups is as dangerous a problem the government can have." He added, "This should send a chill up your spine. ... I don't know where it stops or who is involved. Congressional Republicans already are conducting several investigations and asked for more. "This mea culpa is not an honest one," said Rep. Darrell Issa, R-Calif. After the AP report Saturday, White House press secretary Jay Carney said that if the inspector general "finds that there were any rules broken or that conduct of government officials did not meet the standards required of them, the president expects that swift and appropriate steps will be taken to address any misconduct." Collins said the revelations about the nation's tax agency only contribute to "the profound distrust that the American people have in government. It is absolutely chilling that the IRS was singling out conservative groups for extra review. She said she was disappointed that Obama "hasn't personally condemned this." The president, Collins said, "needs to make crystal clear that this is totally unacceptable." Lerner said that about 300 groups were singled out for additional review, with about one-quarter scrutinized because they had "tea party" or "patriot" somewhere in their applications. Collins appeared on CNN's "State of the Union," Rogers was on "Fox News Sunday" and Issa spoke on NBC's "Meet the Press."