Syria's key opposition National Coalition will not take part in talks with the U.N.'s peace envoy, instead delivering him a letter stating their position, a member told AFP on Monday.

Hisham Marwa, deputy head of the coalition, which is recognized by much of the international community, dismissed the talks with U.N. envoy Staffan de Mistura as "unimportant."

Stung by recent losses, Syria's regime is making a concerted push to reach besieged forces trapped in the rebel-held town of Jisr al-Shughur, hoping to give supporters a much-needed morale boost.

The strategic town in northwestern Idlib province fell to rebels including Al-Qaida's local affiliate just over two weeks ago, but a group of regime loyalists remain trapped inside a hospital complex.

The Kataeb Party warned on Monday that the developments along Lebanon's border with Syria in the east “bring the country back into the circle of danger,” urging the adoption of protective measures to tackle them.

It said in a statement after its weekly politburo meeting: “The government should take the decision to deploy the army along the border with Syria.”

At least 72 fighters were killed in a single day as the Syrian army battled to relieve some 250 besieged regime loyalists under rebel assault, a monitoring group said Monday.

President Bashar Assad had personally pledged to rescue the trapped troops and civilians, who are said to include senior figures and have been holed up in a hospital complex since rebels captured the northwestern town of Jisr al-Shughur two weeks ago.

An Australian teenager charged with involvement in a "well advanced" terrorist bomb plot was remanded in custody Monday, with the 17-year-old saying nothing during a brief court appearance.

Police allege the boy, who was arrested during a raid on his family home in a Melbourne suburb on Friday and cannot be named for legal reasons, was planning to target a public event.

In the pockets of the rugged mountains near the Lebanese border, the distinctive yellow flag of Hizbullah now flies where al-Qaida militants once held sway.

These gains in the Qalamoun Mountains represent a bright spot for embattled Syrian President Bashar Assad's government, now reeling from a unified insurgent assault in the country's northwest. And again, they show the influence of the Lebanese group in Syria's civil war, grinding on into its fifth year after more than 220,000 people were killed.

Turkish Prime Minister Ahmet Davutoglu slipped across the border into Syria on Sunday to visit a historic tomb that was relocated earlier this year away from jihadi-controlled territory.

Davutoglu, accompanied by his defense minister and army commanders, made the surprise visit to the tomb of Suleyman Shah, grandfather of the Ottoman empire's founder Osman I, his office announced.

Rebels including an al-Qaida affiliate stormed a complex in northwestern Syria on Sunday where some 250 regime forces and civilians have been trapped for two weeks, a monitoring group said.

The Syrian Observatory for Human Rights said rebels had entered the hospital complex in the town of Jisr al-Shughur, the rest of which they captured a fortnight ago.

Municipal chief of Arsal Ali al-Hujeiri stressed that the battles between Hizbullah and the Syrian regime against opposition groups have not reached the northeastern border town, reported the Kuwaiti daily al-Anba on Sunday.

He told the daily: “Hizbullah does not have any fighters in Ras Baalbek or on the outskirts of Arsal.”

Syrian government forces advanced Saturday towards the rebel-held town of Jisr al-Shughur, where around 250 regime force members and their families are trapped in a hospital building, a monitor said.

The Syrian Observatory for Human Rights said government troops were now within two kilometers (just over a mile) of where the group has been trapped since rebels seized Jisr al-Shughur in northwestern Idlib province two weeks ago.