National Bureau of Investigation (NBI) Director Melvin Matibag said he will no longer attend a regional summit in Bangkok, Thailand, after the Senate impeachment court scheduled his testimony in the impeachment trial of Vice President Sara Duterte on 21 July.

The two-day regional summit on transnational crime, hosted by the Federal Bureau of Investigation (FBI) and the Royal Thai Police, is set for 21 and 22 July.

"We're not going there anymore," Matibag told reporters.

He said he has designated an NBI representative to attend the summit in his place.

Matibag had earlier written Chief Impeachment Prosecutor and Batangas Rep. Gerville Luistro, requesting that his testimony be scheduled before 20 July because of the international meeting.

However, the Senate impeachment court on Monday set his appearance for 21 July.

The prosecution is expected to present Matibag as a witness on Article IV of the Articles of Impeachment, which concerns Vice President Duterte's alleged threats against President Ferdinand Marcos Jr., First Lady Liza Araneta-Marcos, and former House Speaker Ferdinand Martin Romualdez.