TRIPOLI, Lebanon: Hundreds of protesters hit the streets in north Lebanon Friday to support the Syrian revolt against Bashar al-Assad, organizing blood drives and marching towards the volatile border.

Some 500 Lebanese and Syrians rallied near a border crossing in the Lebanese district of Wadi Khaled, which straddles the Syrian border, amid tight security.

Around 500 others, mainly Islamists, staged a sit-in in the northern port city of Tripoli, which has witnessed clashes between Sunnis and minority Alawite Muslims loyal to the Assad family.

Student activists across Tripoli also set up a handful of tents to host blood drives and gather donations to aid injured Syrian refugees who have regularly crossed into Lebanon in recent weeks to seek medical care.

"We began this campaign after it became clear that the Lebanese government and the institutions that should be concerned with this cause were not doing their job," said Mohammed Taha, a Lebanese student who was helping set up the makeshift donation centres.

"All the money we gather here will be donated to Syrian refugees in Lebanon, and only to these refugees."

Ahmed Moussa, another student activist in Tripoli, said the grassroots campaign to aid refugees had begun weeks ago.

"We started by setting up donation booths outside mosques after Friday prayers and distributing discs documenting human rights violations in Syria to passers-by for free," Moussa told AFP.

Thousands of Syrian refugees have fled to Lebanon as the state cracks down on a popular revolt against the Assad regime, now in its tenth month.

But many say they do not feel safe in Lebanon where Shiite militant group Hezbollah, a staunch ally of Assad, dominates the government.

The Syrian army last month laced the Lebanese border with landmines in a bid to curb arms smuggling and hampering army defectors and refugees from fleeing.

Syrian troops have also staged deadly incursions into border villages in neighboring Lebanon.

The United Nations estimate earlier this month that more than 5,000 people have been killed in the crackdown since protests against the Assad regime began in mid-March.