Massachusetts Congressman Barney Frank has said President Barack Obama's decision not to support gay marriage is “a problem.”

The president was criticized this week for not making mention of Amendment One, the proposed amendment to the North Carolina Constitution which would ban gay marriage, as well as civil unions and domestic partnerships for gay couples, during a trip to the state.

“It's not a surprise,” Frank told The Hill. “He hasn't yet said that he's for [gay] marriage, so that's a problem.”

However, Frank, who is planning to marry his long-term partner Jim Ready in July, gave Obama an overall “A-minus” on gay rights, praising his decision to no longer defend the Defense of Marriage Act (DOMA), which bans federal agencies from recognizing the legal marriages of gay couples, and his leadership on repeal of “Don't Ask, Don't Tell,” which outlawed gay and bisexual troops from serving openly.

“He's been good [but] he hasn't been perfect,” Frank said. “He just hasn't quite gotten to the marriage [issue.]”