DAVAO CITY -- Presumptive President Rodrigo Duterte is planning state visits to the Vatican, the United States, China and Japan, his spokesman said Tuesday.

Duterte will visit the Vatican to "apologize and pray," spokesman Peter Laviña told reporters.

Asked if Duterte will apologize specifically for cursing Pope Francis, Laviña said: "He already wrote a letter."

READ: Duterte: Vatican has forgiven me for 'cursing' Pope

The 71-year-old tough-talking mayor will visit US, China and Japan to strengthen ties with "trading and economic partners," Lavina said.

Duterte had chastised US Ambassador to the Philippines Philip Goldberg for criticizing him for a joke he made on the rape of an Australian missionary in Davao in 1989, even threatening to cut diplomatic ties.

READ: Duterte risks chill in US-PH ties with trash talk

He also expressed openness to cooperating with China in disputed waters and promised to ride a jet ski to plant the Philippine flag on a Chinese-held reef.

READ: Duterte wants to be a hero in dispute vs China