Saudi Arabia on Tuesday summoned Lebanon's ambassador to the kingdom to protest "insulting" remarks by his country's foreign minister, who appeared to blame Gulf states for the rise of the Islamic State group.
Saudi Arabia seems to have taken a step back from its former ally, angered by the influence of Lebanese Shia movement Hezbollah, which is backed by Riyadh's rival Tehran.
Lebanon's outgoing foreign minister Charbel Wehbe stoked fresh tensions on Monday when he suggested during a televised debate that Gulf states were behind the rise of the extremist group in Iraq and Syria.
He made the comment during a verbal duel with a Saudi guest on the show, who blamed Lebanon's President Michel Aoun for "handing over" his country to Hezbollah.
In a statement, the Saudi foreign ministry strongly condemned Wehbe's "insulting" remarks, saying they were "inconsistent with the simplest diplomatic norms".
The ministry "summoned the Lebanese ambassador to express the kingdom's rejection and denunciation" of his comments, said the statement released by the official Saudi Press Agency.
The ambassador was handed an official "letter of protest", the statement added.
Wehbe apologised Tuesday for his remarks, saying he did not mean to offend "brotherly Arab countries".
Faced with a crippling economic crisis, Lebanon's government also moved swiftly to distance itself from the remarks that angered Riyadh, once a key financial backer of Beirut.
Aoun said the remarks were Wehbe's "personal opinion" and did not reflect the position of the state, as he lauded the "brotherly" ties with Saudi Arabia and the Gulf.
Lebanon's outgoing premier Hassan Diab said he had sought an explanation from Wehbe, adding that his country was keen to maintain the "best relations" with Saudi Arabia and the Gulf.
Saad Hariri, the prime minister-designate who owes much of his family fortune to Saudi backing, also slammed Wehbe, saying his remarks were "not in accordance with diplomatic norms".
Last month, Saudi Arabia announced it was suspending fruit and vegetable imports from Lebanon, saying shipments were being used for drug smuggling and accusing Beirut of inaction.
The decision was a blow to Lebanon, which is facing its worst economic crisis since the 1975-1990 civil war.