The US Embassy in Lebanon was set on fire after hundreds of pro-Palestine protestors took to the streets to slam Israel's ongoing airstrikes on Gaza.

The government of Benjamin Netanyahu authorised near non-stop bombings on the strip to root out Hamas fundamentalists following the massacre of thousands of Israelis on October 7.

US military groups deployed smoke and gas to disperse the protestors who gathered at the embassy following an attack on a hospital in Gaza. Hours after the protests began, the State Department issued the travel advisory.

'The Department authorized the voluntary, temporary departure of family members of US government personnel and some non-emergency personnel from US Embassy Beirut due to the unpredictable security situation in Lebanon,' the announcement read.

Pro-Palestine protests have broken out in the Middle East after a blast at the hospital that killed at least 500 people. Palestine blamed Israel and said it was a targeted air strike. Israel contends it was a misfired rocket from inside Gaza that hit the facility.

Iran-backed Hezbollah, which fought a war with Israel in 2006, called for a day of unprecedented anger in Beirut on Tuesday in response to the attack.

Americans are also being advised to avoid the border with Syria due to terrorism and armed conflict, the border with Israel, and refugee settlements.

On Tuesday, thousands of Lebanese protesters, some waving Palestinian flags, gathered outside the US embassy. Video shows the protestor scaling a barb-wire-topped fence to replace a US flag with a Palestinian version. A fire was also set near the complex. Later, footage showed gas being sprayed at the protestors to push them back.

It's unclear if any protestors have breached the perimeter fence or if any embassy personnel have been hurt.

It's unclear if the protesters are marching on the old embassy in Lebanon or the new one that began construction in April 2017, a 43-acre compound that has caused controversy in the country.

An initial press release described it as a $1billion project, according to The Independent. Objectors complained about the price tag and the size of the embassy given so few Americans travel to Lebanon.