Washington, D.C ? The head of the Republican Party is calling on President Barack Obama to withdraw Kathleen Sebelius’s nomination as health secretary unless she answers more questions on abortion.

Republican National Committee Chairman Michael Steele says that Sebelius, the Democratic governor of Kansas, has not been forthcoming about her ties to a Kansas abortion doctor, George Tiller.

Steele’s statement Thursday came as Republicans blocked action on Sebelius’ confirmation in the Senate.

Sebelius was approved by the Senate Finance Committee this week with just two GOP votes. Several Republicans were concerned about her initial failure to disclose how much campaign money she got from Tiller.