Saudi Arabia has asked its citizens to leave Lebanon due to the risk of political violence in the country, where twin suicide bombings near Iran's embassy in Beirut killed 25 people this week.

Riyadh has issued several similar calls in the past two years as the civil war in Syria has inflamed political and sectarian tension in neighbouring Lebanon.

"Saudi ambassador Ali Awadh Al-Asseiri said on Thursday... that the embassy urged Saudi nationals to leave Lebanon, considering the alarming security situation," the Lebanese National News Agency reported, citing a phone call with Asseiri.

Some Shi'ite commentators in Lebanon have accused Saudi Arabia of being behind Tuesday's blasts near the embassy of its main Middle East rival. A Lebanese-based Sunni militant group close to Al Qaeda has claimed responsibility.

An Iraqi Shi'ite militia said on Thursday it was behind the firing of six mortar bombs across the border into Saudi Arabia in an attack the day before that Riyadh said caused no damage. - Reuters