The wife of former Filipino President Joseph Estrada, Senator Luisa "Loi" Ejercito, was detained on Monday for one-and-a-half hours at the San Francisco International Airport where US Homeland Security officers asked her questions, said Philippine Senate President Franklin Drilon on Tuesday.

The US officers asked her several questions, including whether she thought her husband, former President Estrada, would be convicted of plunder, according to Drilon.

Drilon denounced what he said was "maltreatment" of Ejercito in US and said US Ambassador Francis Ricciardone had called him up to apologize for the incident.

Drilon said he received a call from Ejercito Tuesday morning complaining about the incident.

Ejercito told Drilon that when she arrived in San Francisco with her daughter Jackie Estrada-Lopez and her grandchildren on March 20, a team from the US Homeland Security met them at the arrival tube and segregated them from the rest of the passengers.

She was in the US to meet members of various Filipino communities.