WASHINGTON, July 7 (Xinhua) -- U.S. President Barack Obama on Wednesday made recess appointments to fill the post of Medicare and Medicaid chief, bypassing Senate scrutiny.

Obama named healthcare expert Donald Berwick to be administrator of the Centers for Medicare and Medicaid Services under the Department of Health and Human Services, placing him in a vital position to carry out the historic healthcare reform.

Congress is in recess this week, and by law, Obama can fill top administration posts during the period without the Senate approval normally needed.

The nomination of Berwick faced bitter opposition from Senate Republicans. Obama said it's "unfortunate that at a time when our nation is facing enormous challenges, many in Congress have decided to delay critical nominations for political purposes."

Obama urged the Senate to act quickly on the more than 180 nominations still pending. He also named Philip E. Coyle III to be associate director for National Security and International Affairs in the Executive Office of the President, and Joshua Gotbaum to be director of the Pension Benefit Guaranty Corporation.