Hizbullah chief Sayyed Hassan Nasrallah on Saturday pledged that his group would respond to any Israeli airstrike on Lebanon, as he described the probe into the Beirut port blast as “politicized and selective.”

The U.N. Special Coordinator for Lebanon Joanna Wronecka has been following with "great concern" the exchange of fire across the Lebanese-Israeli border in the last days, her office said, following Friday's major flare-up.

"Exercising her good offices, the Special Coordinator has activated her political contacts and reached out to all stakeholders concerned," her office said in a statement.

The United States has urged Lebanon's government to prevent militants from firing rockets into Israel, as tensions between Israel and Hizbullah flared after the group fired rockets at the occupied Shebaa Farms in response to an Israeli airstrike in south Lebanon.

Israeli Defense Minister Benny Gantz on Friday warned Hizbullah and Lebanon not to “test” Israel, after Hizbullah claimed responsibility for firing rockets at the occupied Shebaa Farms in response to Thursday’s Israeli airstrike in south Lebanon.

President Michel Aoun received reports from the Army Command about the developments of the Lebanese-Israeli fire exchange on Friday, the Presidency said in a statement.

The army reports included the measures taken by the army to restore calm and stability in the region, in cooperation with the UNIFIL, the Presidency added.

Former premier Saad Hariri on Friday described the situation on the Lebanese-Israeli border as “very, very dangerous,” after Hizbullah and Israel traded fire across the volatile frontier.

“It represents an unprecedented threat to (U.N. Security Council) Resolution 1701,” Hariri added in a statement.

Head of Lebanese Forces Samir Geagea tweeted Friday, after cross-border rocket fire exchanges between Hizbullah and Israel, that “what is happening is very dangerous, especially amid the great tension in the region.”

He added that the Lebanese are already suffering and warned that “playing with fire” might “eradicate the rest of the Lebanese population.”

Hizbullah said in a statement Friday that a number of citizens intercepted Hizbullah fighters in Shwaya at 11:15 a.m. after they had targeted Shebaa Farms with rockets, in a response to Israel’s previous attacks.

A video widely shared on social media showed angry villagers blocking the truck's passage and accusing Hizbullah of endangering civilian lives by launching rockets from close to residential areas.

UNIFIL Head of Mission and Force Commander Major General Stefano Del Col is in direct contact with the parties over Friday’s hostilities on the Lebanese-Israeli border, UNIFIL said.

The fifth meeting between President Michel Aoun and Prime Minister-designate Najib Miqati, following the port blast's first anniversary, was positive compared to the previous ones, according to media sources.

Sources have informed al-Joumhouria newspaper that Aoun has discussed with Miqati a “new and positive” approach, which was sent to the PM-designate through a special envoy on Wednesday.