Two suicide bombers from Al-Qaeda-linked groups blew themselves up at an army post in the Syrian town of Nabk Wednesday, halting an advance by government forces near the Syrian-Lebanese border, activists said. 
The suicide attacks come a day after troops loyal to President Bashar Assad made gains in the Qalamoun area north of Damascus. 
The British-based Syrian Observatory for Human Rights said the suicide bombers attacked the army checkpoint in explosive-laden cars.
The activist group said the blasts coincided with a rebel attack on the nearby government-held town of Deir Atiyeh, which had not previously been involved in the fighting.
“This seems to have temporarily stopped the army’s advance,” the Observatory’s head, Rami Abdel-Rahman, said of the checkpoint assault.
The attacks by the Islamic State of Iraq and Greater Syria (ISIS)  and the Nusra Front, two Al-Qaeda-affiliated groups, came after rebels were driven out of nearby Qara village Tuesday.
“At least seven regime troops were killed in the two attacks [in Nabk] and five others are in critical condition,” Abdel-Rahman said.
A Syrian security source told AFP there was just one explosion at a checkpoint in Nabk. “The soldiers at the checkpoint stopped a suspicious car and the driver, who was a suicide bomber wearing an explosive belt, tried to escape but was shot dead by soldiers.”
“However, the vehicle exploded,” the source added, citing an unspecified number of casualties.
SANA also reported two suicide attacks in front of Bassel Hospital in Deir Atiyeh, a majority Christian town in army control north of Nabk. 
“Several guards were killed, then the terrorists broke into the hospital and tried to destroy the equipment but the army managed to chase them down,” the agency said.
The Observatory said the rebels had entered the hospital and captured a wounded officer, before being thrown out by the army, leaving the man behind.Militants with the hard-line Nusra Front said their group, along with ISIS, had sent hundreds of fighters to the Qalamoun front in recent weeks.
“There could be more special attacks like what you saw today,” said a source linked to Nusra Front who declined to be named. “The regime has a better chance of winning but the fighters have prepared some surprises with the help of God.”
Some opposition sources have blamed the Islam Brigade, which is not aligned with the mainstream rebel Free Syrian Army, for not providing sufficient support for the rebel stand in Qara and other areas of Qalamoun.
Fighting raged elsewhere in Qalamoun, mainly around the rebel bastion of Yabroud , which the army shelled Wednesday.
Elsewhere, a mortar bomb struck near central Damascus’ Umayyad Square, and two others hit the capital’s Qassaa neighborhood, the Observatory said. Social media networks claimed that a façade in the mosque was damaged by the mortar bomb.
Activists and the Observatory said that fierce fighting also took place between government troops and rebels in areas near Aleppo, as well as the northern town of Tabqa, on the Euphrates River.
In a sign of the stepped-up military campaigns underway, the Observatory said that out of Tuesday’s death toll of 140 people, 102 were either government soldiers or rebels.
In the northern town of Raqqa, Al-Qaeda-linked jihadists of the Nusra Front threw their black flag over a Shiite shrine, in yet another sign that the conflict is becoming increasingly sectarian, the group added.
The Observatory, citing reports from activists, added that ISIS militants in the city of Tal Abyad in Hassakeh publicly executed two Kurdish members of the YPD militia, seen as aligned with the regime.
The border bombings follow the Syrian government's announcement that it has endorsed dropping its longtime lax entry policy for Arab nationals, according to state news agency SANA.
The move came during a Cabinet meeting chaired by Prime Minister Wael Halqi, the agency said Wednesday.
In place since 1970, Syria’s policy of not requiring entry visas for most Arab nationals has increasingly come under fire from government loyalists during the uprising, because Arabs from a range of countries have entered the country and fought for Islamist groups seeking to topple the regime.
However, the majority of these nationals have entered Syria via rebel-held border crossings, or else illegally.
The government cited “changes over the last three decades, particularly the rise in cross-border travelers,” as the reason behind the move.