MANILA, Dec. 27 (Xinhua) -- The Philippines will require Americans to get visas before entering the country if the United States denies entry of Philippine officials involved in the detention of the country's opposition Senator Leila de Lima, the presidential spokesperson said on Friday.

"Should a ban from entry into U.S. territory be enforced against Philippine officials involved in - or by reason of - de Lima's lawful imprisonment, this government will require all Americans intending to come to the Philippines to apply and secure a visa before they can enter Philippine territory," the Philippine Presidential Spokesperson and Chief Presidential Legal Counsel Salvador Panelo told a news conference.

U.S. citizens planning to enter and visit the Philippines for 30 days or less do not need a visa prior to travel to the Philippines provided their U.S. passport is valid and they have a valid return ticket.

Panelo's announcement came a few days after news came out that U.S. President Donald Trump approved last week the U.S. 2020 budget that includes a provision denying entry to those involved in the detention of Philippine opposition Senator de Lima.

The prohibition on entry was part of the general provisions of the State and Foreign Operations Appropriations bill signed into law by Trump. It tasks the U.S. Secretary of State to prohibit from entering the United States Philippine officials about whom he has "credible information (to) have been involved in the wrongful imprisonment" of de Lima.

Also on Friday, Panelo said Philippine President Rodrigo Duterte "is immediately ordering the Bureau of Immigration to deny U.S. Senators Dick Durbin and Patrick Leahy - the imperious, uninformed and gullible American legislators who introduced the subject provision in the U.S. 2020 Budget - entry to the Philippines."

He further said that "the Philippine Supreme Court, the highest court of our land, has affirmed the incarceration of Senator de Lima as valid and lawful."

Senator de Lima has been detained over drug-related charges since February 2017.