King Abdullah of Saudi Arabia and Bashar al-Assad, Syria's president, have arrived in Lebanon in a bid to ease tensions in the country.br br A UN investigation into the 2005 assassination of Lebanon's former prime minister Rafiq al-Hariri is likely to implicate Hezbollah members.br br Hassan Nasrallah, Hezbollah's leader, has warned that such a move could plunge Lebanon back into chaos.br br Syria backs the Hezbollah opposition while Saudi Arabia supports Lebanon's government.br br The combined visit by both leaders is meant as a show of support for stability in the country.br br Al Jazeera's Rula Amin reports.