Washington (AFP) - The subjects were serious enough at President Barack Obama's impromptu press conference Thursday, but many viewers and the collective press corps seized on something more immediately visible: his tan suit.

The president's decision to address the media in a breezy, light-colored summer suit swiftly took center stage for many even as he addressed Russian responsibility for rebel actions in Ukraine and ongoing US air strikes against Islamists in Iraq.

"Yes we tan!" became the mocking rally cry on social media as Obama gave a statement and then took questions from what some have deemed a horrified press corps.

Back in 2012 Obama told Vanity Fair that "I wear only gray or blue suits." By breaking that promise Thursday -- even with what many acknowledge was a sharp-looking, seasonal get-up -- Obama inadvertently gave birth to #suitgate.

And the snark from America's aspiring fashion critics exploded on Twitter.

"I'm sorry but you can't declare war in a suit like that," guffawed Wall Street Journal reporter @damianpaletta.

"The Audacity of Taupe," tweeted Jared Keller, a programming director at startup MicNews.

Other comments were similarly charitable.

"I hope they have a suitable strategy to keep isis at beige, i mean what?" tweeted Washington Post blogger Alexandra Petri (@petridishes).

Not everyone was amused. Someone immediately started the parody handle @Obamasuit, but Twitter has already suspended the account.