The White House says President Barack Obama's lawyers have concluded that no member of his White House staff engaged in improper conduct in Cartagena, Colombia.

Obama spokesman Jay Carney says the White House counsel's office undertook a review as due diligence, even though there were no specific allegations of misconduct against advance White House staff. The Secret Service and the Pentagon are conducting investigations into allegations that agents and military personnel consorted with prostitutes in advance of Obama's trip to the Summit of the Americas.

Last week, Sen. Charles Grassley, R-Iowa, urged a broader investigation to include White House advance staff members, who help set up a presidential trip ahead of Obama's arrival, and personnel from the White House Communications Agency, who work for the U.S. military in support of the president.