A coalition of Bay Area Asian American community groups came out Friday to support boycotting United Airlines.

The groups said while there is no evidence the forcible removal of Dr. David Dao was racially motivated, they said the airline's refusal to say how passengers are selected for removal is frustrating.

"The selection criteria of United Airlines has got to be disclosed so that we root out any possibility of racial discrimination," said Frank Yee, Organization for Justice and Equality.

At a news conference in San Francisco, the groups said they are contacting lawmakers to try to get United to be more transparent and to get policies changed for overbooking flights. The group said it's possible United's policies inadvertently discriminate against foreign travelers or immigrants.

"They might speak a different language when they're on the plane," said George Yang, a community activist. "They might not have understood what the police officers or airline personnel tell them. So these are concerns that may be specifically unique to immigrant communities."

But the group made one thing clear.

"It's not for us to prove that they're right or wrong about the issue -- the racial issue -- it should be United Airlines proving to us that it's not a racial issue," said Carl Chan, Asian Americans for Politicial Advancement.

The group on Friday also showed some letters of support it is already getting from local, state and federal lawmakers. The group said they have not received a response from United.