President Barack Obama reiterated his support for gay rights on Monday. He spoke at a White House reception for lesbian, gay, bisexual and transgender rights advocates.

The event was held to commemorate the 40th anniversary of the beginning of the modern gay rights movement.

Some activists have complained that the president has not fought for their causes enough, criticism Mr. Obama tried to address today.

“We are all witnesses to monumental changes in this country,” Obama said. “That should give us hope. But we cannot rest. We must continue to do our part to make progress, step-by-step, law-by-law, mind by changing mind. And I want you to know that in this task, I will not only be your friend, I will continue to be an ally and a champion and a president who fights with you and for you.”