U.S. congressional Republicans completed the first step Friday toward their long-promised repeal of Obamacare, but now they face the much more difficult task of finding a way to unravel the massive health care law and replace it.

After promising to undo President Barack Obama's health care law for seven years, Republicans will be trying to craft a repeal and replacement plan under scrutiny from all sides.

Lobby groups representing hospitals, doctors and patients want to make sure that individuals — particularly those who are sick — can keep access to coverage. Meanwhile, insurers, pharmaceutical companies and business groups want to get rid of taxes that help fund the law's coverage expansion.