MANILA (UPDATE) - Sen. Panfilo Lacson on Tuesday told President Rodrigo Duterte to read the 1987 Constitution after the latter bristled over his extortion remark and questioned the lawmaker's role in international agreements.

Lacson over the weekend said a diplomatic approach would be more effective than threatening the US in order to keep the Visiting Forces Agreement.

Duterte said he was the sole architect of the country's foreign policy, adding that Lacson has "nothing to do" with the issue.

• Duterte blasts Robredo, Lacson over US 'extortion' criticisms in VFA threat
• Duterte threat to US over VFA gives impression PH a 'nation of extortionists': Lacson

"Mr President, read the 1987 Constitution. A senator has something to do with international agreements: Article VII SECTION 21. No treaty or international agreement shall be valid and effective unless concurred in by at least two-thirds of all the Members of the Senate," Lacson said in a tweet in response to the President.

In a Teleradyo interview, the lawmaker dismissed Duterte's claims he had the sole power to abrogate treaties. He stressed the Senate's role in the withdrawal from or termination of an international agreement.

"May I respectfully remind the President na basahin 'yong (to read the) Constitution," he reiterated.

Lacson also said the Supreme Court had yet to decide if cancellation of accords requires the senators' approval.

"Lalong may sense 'yong aking sinasabi na teka muna, hindi totoong (What I'm saying makes so much sense. It's not true that) I have nothing to do with it. Kasi (Because I am a) sitting senator ako, I have something to do with it," he said.

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• Senators ask SC to clarify Senate’s role in treaty termination

In March, senators asked the high court to clarify the Senate's role in the cancellation of treaties.

The law requires Senate approval before the president can enter treaties with other countries, but the Constitution does not specify if the same applies to the cancellation of accords.

• IN NUMBERS: How beneficial is VFA to the Philippines?

In a Senate inquiry in February last year, Foreign Affairs Secretary Teodoro Locsin Jr. bared that the Philippines received nearly $1 billion (P50.73 billion) in military equipment, training, aid and funding for various projects just from 2016 to 2019.

Duterte, in a public briefing aired late Monday, said he was not sure if Lacson's statement was "pretended ignorance."

"Sabihin ko sa'yo na you have nothing to do with this. I may accept your comments, but use it in a way… use a language that will promote your person, human being. Hindi 'yung basta-basta ka na lang magpost-post without really finding out whether you are part of it or not. I'm telling you, you are not. Next time, consult a lawyer in your office," he said.

(I'm telling you you have nothing to do with this. Don't just speak up and post something without really finding whether you are part of it or not.)

Duterte last year unilaterally canceled the two-decade-old VFA, in an angry response to an ally, Sen. Ronald Dela Rosa, having his US visa canceled. The withdrawal period has been twice extended to create what Philippine officials have said is a window for better terms to be agreed on.

• PH military keen to keep visiting forces deal with US - Lorenzana

'DIPLOMATIC' LANGUAGE

Meanwhile, Sen. Risa Hontiveros said as the VFA affirms and enables the Mutual Defense Treaty, it is well within her, Lacson's and any other senator's right to speak about it as the Senate is a treaty-making body.

"Ang VFA naman ay dumadaloy mula sa Mutual Defense Treaty and every lawyer worth his or her salt also knows that the Senate is the treaty-making body of our country kaya si Sen. Ping naman ay well within his rights to speak about an executive agreement flowing from a treaty. Si Sen. Ping, ako, buong Senado ay well within our rights to speak about that issue," she told ANC.

(The VFA flows from the Mutual Defense Treaty and every lawyer worth his or her salt also knows that the Senate is the treaty-making body of our country, that's why it is well within Sen. Ping's rights to speak about an executive agreement flowing from a treaty. Sen. Ping, I, and the whole Senate, it's within our rights to speak about the issue.)

Hontiveros said she supports the review of the VFA to make it more "pro-Filipino," including holding American soldiers accountable if they violate Philippine laws.

However, she said Duterte could have used a more "diplomatic" language in asking the US for more aid in exchange for the continuation of the VFA.

Watch more in iWantv or TFC.tv

Watch more in iWantv or TFC.tv