A big black X has been painted on the doors of dozens of Syrian-run shops in Beirut's southern suburb, a bastion of Shiite Damascus regime ally Hezbollah.
The marks have an ominous message: "Do not open for business."
They have been daubed on the doors by relatives of nine Lebanese Shiites kidnapped in neighbouring Syria a year ago and not heard from in four months.
"They will stay shut until our relatives are free," says one family member of the businesses in Hay el-Sellom market.
Not far away, other people set up checkpoints outside Beirut's Tiro industrial area to stop Syrian workers from getting to their jobs.
A dozen unarmed men and women stopped cars at an intersection in the neighbourhood and verify the identities of their passengers. They turned back minibuses driven by Syrians, and did not allow Syrian passengers from continuing onwards.
Explaining that their gesture was a bid to draw attention to the plight of their relatives, they also ejected a group of Lebanese schoolchildren from a bus driven by a Syrian, ordering him to turn back.
"Tell all the passengers to get off, and turn back," they told the driver.
A group of soldiers stood passively nearby, in an area that is normally abuzz with Syrians.
Having heard nothing of their loved ones' fate for so long, the relatives say their action is born from despair.
"We know what we're doing isn't great, but we are so desperate," said Inaya Zogheib, the daughter of one of the hostages.
Mona Termos, whose husband Ali is another of the hostages, said "we have nothing personal against the Syrians; they have lived among us for 30 years."
For decades Syria dominated its smaller neighbour, and thousands of Syrians flocked to more prosperous Lebanon to find jobs that paid better than those at home, a place ravaged for the past two years by a brutal civil war.
But Termos said that "while our relatives are being held in Syria, we won't allow them to have their livelihoods... My husband managed a supermarket, and now my two daughters have left university to keep the family afloat."
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"You should organise sit-ins calling for our relatives to be freed. Otherwise, you won't have the right to work in this country any more!" Termos cried out to a Syrian bus driver.
"I support your cause; I swear to you," he replied helplessly.
The hostages are part of a group of Shiite pilgrims who were kidnapped in May in northern Syria's Aleppo province as they returned from a pilgrimage in Iran. The women in the group and two men were released.
The kidnapping was claimed by a man who identified himself as Abu Ibrahim and said he is a member of the rebel Free Syrian Army, but the FSA denies any involvement.
There have been several failed rounds of negotiations to free the pilgrims.
The kidnappers have not spelled out any demands, though they have claimed that the hostages were members of Hezbollah, the powerful Lebanese Shiite party.
Most of Syria's rebels -- like the population -- are Sunnis. Close Damascus ally Hezbollah has frequently spelled out its unwavering support for President Bashar al-Assad, who belongs to the Alawite sect, on offshoot of Shiite Islam.
Hezbollah chief Hassan Nasrallah said last year that the kidnapping would not affect the group's position on Syria's conflict.
For now, Syrian workers in Lebanon are paying for the families' rage. Mohammed, who works for the Pepsi company, was forced to turn back while on the way to work on Wednesday.
"They've been stopping us from getting to work for 10 days. They don't use any violence... but what can we do to help them," asked Mohammed, who comes from the eastern Syrian province of Deir Ezzor.
Since the Syrian conflict began, more than 400,000 people have sought refuge in Lebanon, putting pressure on the small country's resources and creating tensions with local residents in parts of the country.
In Hay al-Sellom, a group of young Syrian men gathered at the entrances to the closed shops.
"I am losing $250 a day," said Hussein, 26, who runs three toy and garments stores.
There are fears that the situation in Lebanon may degenerate further, as it did in summer last year. Then, dozens of Syrians were kidnapped and their property destroyed after media outlets erroneously reported the death of the kidnapped pilgrims.
"We too have become hostages to the conflict," said Hussein.