Congress is already gearing up to scrutinize the Comcast-NBC deal

The U.S. Congress will investigate Comcast's (CMCSA) proposed $30 billion merger with NBC Universal, a powerful House committee chairman said hours after the deal was announced on Thursday. The hearings will likely be the focal point of intense government scrutiny of the pact, which unites two of the biggest media companies in the world.

The Federal Communications Commission is also expected to examine the deal. News of the government probes -- while expected -- comes as interest groups unloaded on the proposed megamerger. "This deal is a witch's brew," says Art Brodsky, spokesperson for Public Knowledge, a Washington, D.C., advocacy group that has tangled repeatedly with Comcast over broadband policy issues.