BEIRUT — On Tuesday, President Michel Aoun called for forgiveness and stability in Lebanon after a political row involving his son-in-law triggered street protests and deepened a rift with Parliament Speaker Nabih Berri.

Foreign Minister Gebran Bassil called Parliament Speaker Nabih Berri a “thug” in a closed meeting.

Berri supporters set ablaze tires and blocked roads on Monday in protest against comments by Bassil, who had called him “a thug” in a video that went viral on social media in Lebanon.

“What happened on the ground is a big mistake based on a mistake,” Aoun said in a statement. “I forgive all those who assaulted me and my family, and I look to those who insulted each other to forgive each other,” he said.

The Free Patriotic Movement party, founded by Aoun, said Bassil had already expressed regret for the comments and as far it was concerned the issue was over. Berri supporters have been demanding a public apology from Bassil.

Political tensions between Berri and Aoun have been escalating since December when Aoun signed a decree promoting dozens of army officers without the signature of the Finance Minister Ali Hassan Khalil, one of Berri’s closest aides.

Berri said Aoun exceeded his constitutional powers with the army promotions. Aoun said he did not.

The row over Bassil’s comments threatens to ignite sectarian tensions in the run-up to a parliamentary election in May, and risks paralyzing Prime Minister Saad al-Hariri’s coalition government which groups nearly all of Lebanon’s main parties.

In one incident on Monday, gunfire erupted near offices of Aoun’s Free Patriotic Movement (FPM) east of Beirut. The FPM and the Amal movement led by Berri traded blame.

Bassil expressed regret for his remarks in an interview with the Lebanese al-Akhbar newspaper on Monday, saying he had departed from his moral standards in the closed meeting.

But this did little to ease fury in the Berri camp, which has said Bassil crossed “red lines.”

The FPM, following a meeting of its leadership, said Bassil had “recalled” the leaked comments and expressed regret.

Berri and Aoun, both in their 80s, were on the opposite sides of the civil war in Lebanon that erupted in April 1975. The conflict ended in 1990 when the Syrian army forced Aoun, then head of one of two rival governments, from the presidential palace and into exile in France.

The standoff has also strained Aoun’s political alliance with the Hezbollah, which has longstanding ties to Amal and Berri.

MPs with Hariri’s Future Movement expressed “concerning the level of political dialogue in the country, which reached unacceptable limits, including insulting presidencies and leaders on social media sites.”

They also stressed the importance of upholding the constitution and the peace deal that ended the 1975-90 civil war.

On Thursday, the Amal Movement called on Berri’s supporters to stop protesting in the street, seeking to contain tensions.

“We ask all those who took to the streets in an unorganized and spontaneous manner … To halt any movements in the street,” Amal said in a statement.

Amal thanked its supporters for condemning Bassil’s remark but said this had led to “some problems which do not reflect the image and position of the Amal Movement.”

The FPM said on Tuesday that Bassil had already expressed regret for the comments and that it regarded the issue as over. Berri said on Wednesday he must apologize “to the Lebanese people” for the remark.