Under fire from angry Republicans, US Vice President Joe Biden's office said Tuesday that he firmly opposes "repugnant" Chinese population control practices like "forced abortion and sterilization."

"The Obama Administration strongly opposes all aspects of China's coercive birth limitation policies, including forced abortion and sterilization," Biden spokeswoman Kendra Barkoff told AFP by email.

"The Vice President believes such practices are repugnant," she said after Republican White House candidates blasted Biden for recent comments he made about Beijing's "one-child" population control policy during a visit to China.

Biden told an audience at Sichuan University in Chengdu, China, Sunday that "your policy has been one which I fully understand -- I?m not second-guessing -- of one child per family."

Former Massachusetts governor Mitt Romney, a leading candidate for the Republican nod to take on President Barack Obama in November 2012 elections, on Tuesday accused Biden of "condoning" a "gruesome and barbaric" policy.

"There can be no defense of a government that engages in compulsory sterilization and forced abortions in the name of population control," he said, charging that Biden's comments "should shock the conscience of every American."

Barkoff pointed out that Biden, who was discussing the ratio of active workers to retirees, had also called the policy "unsustainable" and said "he was arguing against the One Child Policy to a Chinese audience."

But Texas Governor and Romney rival Rick Perry charged that Biden's "refusal to 'second-guess' this horrendous policy demonstrates great moral indifference on the part of the Obama Administration."

"Americans value life, and we deserve leaders who will stand up against such inhumanity, not cast a blind eye," said Perry.

Former US China envoy Jon Huntsman said through an aide that the policy "runs counter to the fundamental value of human life" and that he was "heartbroken" that Beijing's approach "has cost millions of lives."

"As an adoptive father, whose daughter was abandoned by her parents in China, Governor Huntsman is intimately familiar with the impact of China's 'one-child' policy," said the aide, Tim Miller.

The comments came one day after Republican House Speaker John Boehner, the number-three US elected official, said he was "deeply troubled" by Biden's words and that the policy "should not be condoned by any American official."

Obama's "administration should be focusing on jobs for the American people, not encouraging foreign governments to utilize abortion as a means of population and deficit control," said Boehner.

The speaker urged the White House to provide "a correction or clarification" to Biden's comments.

Senator Jim Inhofe, the top Republican on the Senate Foreign Relations Committee's subcommittee on East Asian and Pacific Affairs, charged that Biden's remarks amounted to "trampling on the memory of the millions of children who have lost their lives at the hands of a Communist regime."

"It is sad that our vice president lacks the courage and moral fortitude to stand up for what is right and defend those that have no voice," he said in a statement on Tuesday.

The vice president's statement also drew fire from a leader of the repressed Tiananmen Square protests, Chai Ling, who has become a born-again Christian and activist against the "one-child" policy.

"At best, it is a statement of ambiguity that gives permission to China to continue its brutal and coercive birth planning policy," said a statement from her advocacy group, All Girls Allowed.

"At worst, it is an endorsement of the exorbitant fines, severe beatings, and forced abortions and sterilizations that are performed on thousands of Chinese families every day -- an ongoing Tiananmen massacre every hour," she said.