Seeking to neutralize political opposition to its proposed merger with NBC Universal Inc., Comcast Corp. says it will add four cable networks owned, or partly owned, by African Americans over the next eight years, as well as a new English-language channel aimed at Asian Americans.

Those provisions are part of separate agreements Comcast executives signed with civil rights groups.

The African American agreement will be filed Friday with the Federal Communications Commission, Comcast said, and the Asian American agreement was filed earlier in the week. Both call for Comcast to boost diversity in its corporate management and entertainment content and to establish councils to review diversity projects.

"We had been working with NBC for a decade, but Comcast did not have much of a track record with the Asian American community," Karen Narasaki, president of the Asian American Justice Center in Washington, said Thursday.

One criterion the FCC will evaluate in considering the "public benefit" of the Comcast-NBC Universal deal is the diversity of voices in media that will result from the cable and entertainment giants' merger.

Comcast has said it would like to conclude its merger with NBC Universal by the end of the year, but time seems to be running short, with the holidays and the net-neutrality issue before the FCC.

The Justice Department also has to give its consent to the merger.

African American groups that signed the agreement to be filed with the FCC were the NAACP, the National Urban League, and the Rev. Al Sharpton's National Action Network, according to a memorandum of understanding between the groups and Comcast.

According to that agreement, the four channels added to the Comcast lineup will be majority-owned or substantially owned by African Americans. The channels will be added to Comcast over eight years.

Asian groups signing the separate agreement were the Asian American Justice Center, East West Players, the Japanese American Citizens League, the Organization of Chinese Americans, and the Media Action Network for Asian Americans.

"We are trying to create an economic model to show that Asian American content can be profitable," Narasaki said.

The English-language channel that Comcast has agreed to add does not yet exist, she said.