DAMASCUS, Feb. 25 (Xinhua) -- Activists said that Syrian airstrikes and shelling were renewed against the rebel-held Eastern Ghouta countryside of the capital Damascus on Sunday.

The airstrikes were renewed on the town of Sheifonieh in Eastern Ghouta on Sunday morning, said the Syrian Observatory for Human Rights.

The London-based watchdog group said that three people were killed in Eastern Ghouta by the Sunday shelling.

A day earlier, and after marathon talks and discussions, the UN Security Council adopted a resolution to establish a 30-day nationwide cease-fire in Syria "without delay" to ensure the delivery of humanitarian aid to the affected people in Eastern Ghouta and other hotspots across the country.

The resolution, however, excluded the military operations against Islamic State (IS) and the al-Qaida-linked Nusra Front from the cessation of hostilities.

The Observatory said the night after the resolution was calm before the airstrikes and shelling were renewed Sunday.

The Syrian army claims its fighting al-Qaida-linked terror groups in Eastern Ghouta, which explains the ongoing military operation in that area despite the adoption of the new resolution.

Meanwhile, some pro-government activists said the Syrian army has launched a ground offensive on areas in Eastern Ghouta on Sunday to eliminate the al-Qaida-linked groups, capturing the Nashabiyeh area in the sprawling Ghouta area.

A couple of months ago, the rebels, mainly the al-Qaida-linked ones, launched a major offensive on a key military base in Harasta city in Eastern Ghouta, prompting the Syrian forces to launch a counter-offensive to push back the rebels.

However, the rebels renewed their mortar shelling on the capital, bombarding residential areas and sending the civilians into the fear of death or disability.

The attack has apparently raised the ire of the government, as Eastern Ghouta was supposed to be a de-escalation zone as part of a deal mediated by Russia, Turkey, and Iran.

In recent days, unprecedented military reinforcements started gathering on the outskirts of Eastern Ghouta, with heavy firing at the rebel positions in the area as a prelude to the ground offensive.

Meanwhile, the rebels also intensified mortar shelling on the capital, killing dozens of people and wounding many others.

The Observatory said at least 500 people have been killed by the heavy bombardment on Eastern Ghouta since Sunday.

In addition, pro-government Sham FM documented 338 mortar blasts in Damascus since January and the killing of 79 people, including 17 children.