The United States is considering whether to allow Yemen's outgoing president, Ali Abdullah Saleh, to undergo medical treatment in the U.S. for injuries sustained in an attack on his palace in June.

A senior U.S. official said Monday that Mr. Saleh's office recently requested that he be allowed to receive specialized treatment in the United States. The official said the request would only be approved for medical reasons.

On Saturday, Mr. Saleh said he would travel to the U.S. to calm the atmosphere in Yemen, ahead of presidential elections scheduled for February 21, not for medical treatment. He has said he will return to Yemen at an unspecified date to represent the opposition.

The embattled leader agreed last month to end his 33-year rule amid violent street protests calling for his ouster.

Protests have continued in Yemen despite Mr. Saleh's agreement to vacate the presidency. Pro-government security forces killed nine demonstrators on Saturday as they demanded the Yemeni president be tried for the deaths of more than 1,100 people since January. Protesters object to the immunity granted Mr. Saleh as part of the accord he signed in the Saudi capital, Riyadh.

The White House said President Barack Obama's top counterterrorism advisor, John Brennan, called Yemen's vice president Sunday to emphasize the need for security forces to show “maximum restraint” when dealing with demonstrators.

Vice President Abed Rabbo Mansour Hadi told Brennan he has started an investigation into deaths and injuries that have occurred, and that he would do what he could to prevent further bloodshed. The White House said both officials agreed it is important to stick to the transition path leading to the February 21 elections.

Hadi on Sunday urged Mr. Saleh's foes and loyalists to commit to a truce.