The Free Syrian Army succeeded on Thursday in seizing control for the first time of a border-crossing with Lebanon.

The army took control of the crossing that ties the Syrian town of Rankous to the Lebanese town of Tfeil, which lies in Syrian territory.

U.S. Ambassador to Lebanon Maura Connelly and U.N. Special Coordinator for Lebanon Derek Plumbly held separate talks on Thursday with Prime Minister Najib Miqati on the flow of refugees from Syria to Lebanon.

Connelly praised “the generosity of the Lebanese people and the efforts of the government, in conjunction with international partners and organizations, to provide humanitarian assistance to the growing number of Syrian and Palestinian refugees and affected Lebanese communities.”

Two nephews of Syrian Vice President Faruq al-Sharaa have been arrested along with five of their friends over their support for democratic change, a monitoring group said on Thursday.

"University professor Zaydun Zohbi, 38, and his brother Suhaib, who are nephews of Faruq al-Sharaa, and five of their friends, activists in favor of peaceful change in Syria, were arrested at a cafe on December 15 by members of the military intelligence," said the Syrian Observatory for Human Rights.

Thousands of Palestinians returned on Thursday to a refugee camp in Damascus that has become a battle ground, as U.N. investigators warned of an openly sectarian conflict that threatens whole communities.

Meanwhile, Russian President Vladimir Putin denied propping up President Bashar Assad and stressed that Moscow was only seeking to avert a perpetual civil war in its long-time ally.

Violence in the Syria conflict has become openly sectarian and threatens whole communities, U.N. investigators reported Thursday following a visit to the region.

"As battles between government forces and anti-government armed groups approach the end of their second year, the conflict has become overtly sectarian in nature," the U.N. Commission of Inquiry on Syria said in a report.

The United Nations warned Lebanon on Wednesday that the alleged Lebanese fighting in Syria's civil war put the country increasingly at risk of being dragged into the conflict.

The U.N. Security Council meanwhile expressed concern over Syrian army operations in the Golan Heights ceasefire zone with Israel and said that also threatens to extend the 21-month old civil war.

More than 44,000 people have been killed in Syria since the outbreak in March 2011 of an anti-regime revolt that became a bloody insurgency after a brutal crackdown, a rights group said on Wednesday.

"At least 44,063 people have been killed in 21 months," said Syrian Observatory for Human Rights director Rami Abdel Rahman.

As many as 100,000 Palestinians may have fled a Damascus refugee camp after deadly clashes there, the U.N. agency for Palestinian refugees said Wednesday.

"People are still leaving in droves," UNRWA deputy chief of staff Lisa Gilliam told AFP, adding that the organization estimated that around two thirds of the some 150,000 residents of Yarmuk camp appeared to have left.

First Military Investigation Judge Riyad Abu Ghida received on Wednesday a file on the complete identity of Syrian security chief Ali Mamlouk, reported the National News Agency.

The file contains the name of the mother of the Syrian official, who is charged, along with former Minister Michel Samaha of forming a criminal gang aimed at carrying out attacks in Lebanon at Syria's behest.

Umm Khaled's living room in the Baddawi refugee camp in north Lebanon is now a bedroom for Palestinians fleeing fierce battles in another refugee camp -- in the Syrian capital.

"Twenty people from Yarmuk (in Damascus) arrived at my house, among them children, women and elderly people" on Monday, said Khaled, 50, herself a long-time Palestinian resident of Baddawi.