WASHINGTON — US President Barack Obama's campaign announced Thursday it would start accepting contributions by text message, saying this would help his grassroots re-election effort.

The Obama team "will be the first political campaign in history to accept small-dollar donations via text message," his campaign said in a statement.

The move follows advisory opinions issued by the Federal Elections Commission on the legality of the effort. Supporters can make contributions, not exceeding $50, during any billing cycle for most carriers.

"Grassroots giving is powering this campaign," said Obama campaign manager Jim Messina.

"Since April 2011, more than 2.7 million people have pitched in to own a piece of the president's campaign, and last month 98 percent of donors gave less than $250.

"Accepting small donations by text message will help us engage even more grassroots supporters who want to play a role by donating whatever they can afford to the campaign -- and get the president re-elected in November."

Several US carriers are allowing this and others are expected to join. Text message contributors will see their donations charged to their wireless bill.

"This campaign's strength has always come from the millions of grassroots supporters nationwide who are organizing their communities every day, and this function is another easy, low-barrier way for supporters to help build an unprecedented grassroots organization across the country," the statement said.