BEIJING - One day into the long-awaited cease-fire in Syria, truce was largely observed though sporadic shelling still took place, killing and wounding dozens.

As main backers of the cease-fire, Russia and the United States have exchanged information as the two sides are consulting in Amman, Jordan, over how to uphold the truce.

The Syrian government said it would obey the agreement, but would not stop fighting extremist groups such as the Islamic State (IS).

According to Syrian media, the shelling mostly targeted the capital Damascus, Aleppo and Deir al-Zour.

The Syrian Army General Command said rebels in Jobar and Douma neighborhoods in the suburbs of Damascus fired mortars into the city just hours after the cease-fire went into effect.

It warned of consequences of such attacks and called on the people living in those neighborhoods to pressure the militants from breaking the truce.

Despite the shelling, Damascenes' mood to savor the peace was not dampened, as Xinhua reporters witnessed Saturday in Damascus' commercial al-Qassa area that streets were once again packed by shoppers.

"It's difficult to remember a calm night throughout the last four years, but yesterday was different. Last night was so calm and this peaceful atmosphere has pushed people to go on streets today," said Ahmad, a 30-year-old man from the neighborhood.

Also enjoying the peace were Khitam and her friends, who were strolling on the street.

"We felt the old peace again, especially last night as we slept without hearing the rattling sound of shelling echoing," Khitam said.

As Syrians are taking a breath, Russia and the United States are resorting to multiple measures to ensure the cease-fire will hold.

An official at the Russian Defense Ministry said Saturday that the two powers are exchanging information concerning the cease-fire.

The shared information includes where the latest cease-fire is applied, where armed groups are deployed and where the cease-fire is breached, according to Sergei Rudskoi, the official.

Should cease-fire violations be confirmed, Moscow and Washington will take measures to de-escalate tensions, he said.

In addition to the exchange of information, the two sides have set up a hotline linking Moscow, Washington and Geneva to share intelligence.

Both the United States and Russia have shown sincerity in supporting the cease-fire, as Moscow have brought the Syrian government to the table, while Washington made sure the armed groups it supported abide by the agreement.

It was made clear from the beginning that the cease-fire would exclude extremist groups such as the IS and Jahbat al-Nusra, and all sides have stressed that they would continue combatting terrorism.

However, experts warn that facing growing pressure, extremists may try to sabotage the fragile cease-fire.

Three bomb attacks hit the central province of Hama on Saturday, a signature move of the IS, and the mortar shelling of Aleppo and Deir al-Zour are also believed to have come from the terror group.

Syrian analyst Osama Danula told Xinhua that territories controlled by opposition and extremists often overlap and how to fight terrorist groups with precision will be a "technical difficulty" for Syrian forces.