A strong 6.9 magnitude earthquake rocked southwestern Colombia on Saturday, the US Geological Survey said.
The quake, centered 6 miles (10 km) southwest of Pasto, was 80.5 miles deep (130 km) and was felt as far away as Quito, Ecuador, according to Reuters.
USGS originally reported the quake, which struck at 1416 GMT, as a 7.0 magnitude.
Three more US Secret Service employees are resigning over a scandal in Colombia involving prostitutes, according to the agency.
12 members of the Secret Service have been implicated in the incident, which involved 21 women being brought back to a beachfront hotel ahead of the Summit of the Americas last weekend.
One Secret Service employee was cleared of "serious misconduct" and will face administrative action, the agency said.
President Barack Obama has confidence in Secret Service director Mark Sullivan and believes he acted quickly to deal with a scandal in Colombia where agents were alleged to have engaged in misconduct involving prostitutes, White House spokesman Jay Carney said.
He added that the incident was being investigated and declined to speculate about conclusions that could be reached as a result of that probe.
US Senator Susan Collins has said that "twenty or 21 foreign national women" were brought to the hotel in Colombia by US Secret Service agents and US military, according to Reuters.
Ms Collins was briefed by Secret Service director Mark Sullivan who said that US marines were allegedly involved.
The chairman of the US Joint Chiefs General Martin Dempsey has told a conference in Colombia of his 'embarrassment' about an alleged prostitution probe involving US agents and military officers.
NBC producer Kristen Welker has reported that the US Secret Service has revoked the top secret security clearances of all 11 agents and officers.
"Pending investigation, their top secret clearance has been revoked," George Ogilvie, a Secret Service spokesman, said.
The chairman of the US Joint Chiefs has said that the military is 'embarrassed' by the alleged military involvement in the misconduct scandal in Colombia, stating that "we let the boss down".
Speaking in a news conference, chairman Martin Dempsey said the substance of the Summit of the Americas had been overshadowed by allegations of misconduct by members of the Secret Service and military, which the Colombian police said involved prostitutes.
A prostitution scandal involving US security personnel in Colombia is threatening to eclipse President Barack Obama's charm offensive to Latin America.
In a major embarrassment for the United States at the Summit of the Americas attended by more than 30 heads of state, 11 US Secret Service agents were sent home and five military servicemen grounded over "misconduct" allegations in a hotel.
A US lawmaker who heads a congressional committee that oversees the Secret Service told CNN the incident apparently involved 11 agents "and they did bring women back to their rooms."
A dozen US Secret Service agents sent to Colombia to provide security for President Barack Obama at an international summit have been relieved of duty over alleged misconduct.
A caller who said he had knowledge of the situation told The Associated Press the misconduct involved prostitutes in Cartagena, site of the Summit of the Americas. A Secret Service spokesman did not dispute that.
An unnamed US official put the number of agents sent home at 12 but the Secret Service did not disclose the number of personnel involved. The incident threatened to overshadow Mr Obama's economic and trade agenda at the summit. The White House had no comment but did not dispute the allegations.