DAMASCUS, Feb. 20 (Xinhua) -- The Syrian capital Damascus' Eastern Ghouta area and the Kurdish-held Afrin enclave have grabbed the headlines recently after witnessing intense battles.

Eastern Ghouta, a sprawling suburb constituting of several towns, is seeing some of the most intense shelling by the government forces, which are poised to launch a massive assault to eliminate the al-Qaida-linked groups there.

The presence of the ultra-radical groups is seen by the government as a threat to the security of the Syrian capital.

On Sunday, the Syrian forces started the prelude to a massive ground offensive with heavy fire cover and airstrikes, while the rebels started raining down the capital with mortar shells, almost paralyzing life in eastern neighborhoods close to Eastern Ghouta.

A police source told Xinhua that eight people were killed and 42 others wounded on Tuesday by 42 rebel mortar shells in Eastern Ghouta.

Pro-government activists said that 13 people were killed and 58 others wounded by the explosion of 62 mortar shells, some of which fell on moving cars on main roads.

Three schoolchildren were killed when a mortar shell struck the Dar al-Salam school in central Damascus, while some others were seen in hospitals sustaining wounds from the shelling.

The shelling and the rattling sounds of airstrikes have become the talk of the city, making people in eastern Damascus stop sending their kids to the schools temporarily.

The military campaign aims to end the presence of the rebels in Eastern Ghouta, pro-government media outlets said, but it is no easy task as the rebels have been entrenched there for years.

Four key rebel groups are positioned inside Eastern Ghouta, the Islam Army, Failaq al-Rahman, Ahrar al-Sham and the Levant Liberation Committee (LLC), otherwise known as the al-Qaida-linked Nusra Front.

On the other hand, the opposition activists, mainly the Syrian Observatory for Human Rights, said that 190 people have been killed and 850 others wounded in Eastern Ghouta since the military shelling started on Sunday evening.

The UN has demanded for an end to the targeting of civilians in Eastern Ghouta. "It's imperative to end this senseless human suffering," said Panos Moumtzis, UN's regional humanitarian coordinator for the Syrian crisis.

The Turkey-based Syrian National Coalition, Syria's main opposition group in exile, denounced the shelling on Eastern Ghouta as "war of extermination" as well as the "international silence."

In the north, the Kurdish-controlled city of Afrin, which has been under a month-long Turkish offensive, has seen a new development Tuesday, with the pro-government Syrian fighters entered that large enclave to "help the people of Afrin confront the Turkish attack," reported the Syrian national TV.

The Kurdish People's Protection Units (YPG) said in a statement that they welcome the arrival of the pro-government forces.

The forces reached Afrin, in the northern countryside of Aleppo province, coming from their assembly point in Aleppo city.

In a live broadcast from Afrin, the Syrian state TV showed the soldiers arriving at the al-Ziyara checkpoint at the entrance of Afrin.

The live broadcast also showed the moment when Turkish shelling struck a nearby area while the TV presenter was reporting live. It turned later to be warning shots fired from Turkey to push the pro-government fighters out.

Syria's state media said the forces entered Afrin, while Turkish President Recep Tayyip Erdogan said that a small pro-government militant group retreated after coming under Turkish artillery shelling.

The Turkish army, together with allied Syrian insurgents, unleashed a large-scale offensive on Jan. 20 in a bid to oust the Kurdish YPG fighters from Afrin region.