Clashes occurred overnight Sunday in a number of Syrian areas, witnesses and media reports said.

Overnight Sunday, a number of neighborhoods in Syria witnessed several clashes and chaotic incidents, with circumstances remaining murky.

Al-Watan, a pro-government newspaper, said Monday terrorists struck an armored vehicle with a thermal missile overnight Sunday in the Damascus suburb of Douma, without saying whether the attack had left casualties or not.

In the suburb of Qudsiah, sounds of mortar shells and gunshots reverberated overnight Sunday, witnesses told Xinhua.

Meanwhile, the Syrian authorities thwarted late Sunday an attempt by gunmen to get into Syrian territories from Lebanon and killed all of them, Syria's Arab News Agency (SANA) said Monday.

Also, SANA said that local authorities in Albu-Kamal city in eastern Deirl al-Zour province clashed Sunday with an "armed terrorist group" trying to smuggle a large amount of weapons near the Syrian-Iraqi borders, leaving a number of smugglers injured and the weapons confiscated.

On the opposition side, the Britain-based Syrian Observatory for Human Rights, said a total of 45 people were killed across Syria Sunday, blaming the government troops of the violence.

The Observatory urged UN chief Ban Ki-moon to "personally intervene" regarding the constant bombardment of neighborhoods in the central province of Homs such as Khaldiya, Jourat al-Shayyah, Qarabees, and al-Qusoor among others.

It said more than 1,000 families, including women and children, were stranded in the constantly shelled areas, adding that those families need to be evacuated immediately.

The activists' reports couldn't be independently verified.

In a statement issued Sunday, Maj-Gen Robert Mood, head of UN observer mission in Syria, said that "civilians continue to be trapped by the escalating violence in Syria."

"In Homs, attempts to extract civilians from the line of fire over the past week have been unsuccessful," said Mood, calling on the concerned parties to take immediate action to ease the pain of Syrians trapped in the violence.

Mood stressed that all parties in Syria "must reconsider their position, allow women, children, the elderly and the injured to leave conflict zones, and ensure their safety without any preconditions."

The UN estimates that over 9,000 people have died in Syria's 15- month-old unrest, while the Syrian authorities said they are fighting foreign-backed armed groups and over 2,000 troops were killed during attacks on government establishments.