BEIRUT: Syrian troops pounded several districts of the central city of Homs Wednesday and clashed with rebels as at least 19 people were killed in violence across the country, activists said.

Regime troops rained shells on the besieged, rebel-held district of Khaldiyeh, killing two civilians and wounding seven others, the Syrian Observatory for Human Rights said.

It said living conditions in Khaldiyeh were deteriorating.

Other areas of Homs also saw fierce violence, as regime forces pounded the districts of Sultaniyeh and Jobar, where families trapped by the fighting "are like the living dead," an activist from the central city told AFP via Skype.

"Regime forces shell the Sultaniyeh and Jobar districts daily," said the activist, who identified himself as Abu Bakr.

"Life is down to a bare minimum," in the impoverished neighbourhoods of Sultaniyeh and Jobar and the districts have been without electrical power for days, said Abu Bakr.

Most of the residents have fled but "families that remain here are like the living dead," he added.

"Usually you have four or five families huddling in a ground-floor apartment ready to flee when the shelling starts," he said.

Rebels and troops also clashed on Wednesday around the neighbourhood of Baba Amr -- once a rebel held district which was reclaimed by the Syrian army in March after a month-long campaign of relentless shelling, Abu Bakr said.

"Free Syrian Army battalions are fighting regime troops every day around Baba Amr, trying to retake the district," he said.

Syrian troops and rebels also clashed at dawn at Jaramana, a suburb south of the capital, Damascus, the Britain-based Observatory reported.

The fighting erupted near a branch of the feared air force intelligence service, the watchdog said.

Elsewhere, six civilians were killed in the northwestern province of Idlib, including four who were ambushed and killed by soldiers in the village of Maaret al-Numan, the site of frequent violence, the Observatory added.

Of those killed Wednesday, four were rebels and the rest civilians, the Observatory said.

The latest deaths came a day after violence killed 69 people -- 36 civilians, 25 troops and eight rebels, the Observatory said.

More than 16,500 people have been killed in Syria since the uprising erupted in March last year, it says.

This figure is impossible to independently verify, and the United Nations no longer publishes its own estimates of the death toll.