A 48-hour cessation of hostilities has been declared in the northern Syrian city of Aleppo, the Russian Defense Ministry said.

The Britain-based Syrian Observatory for Human Rights and a number of activists reported relative calm in the country’s largest city on Thursday.

In past months, Aleppo has witnessed fierce fighting and bombardment, which has claimed the lives of hundreds of people on both sides of the contested city.

Russia said the truce went into effect after midnight Wednesday. Several similar truces have been declared in the city in recent months.

It said that since the latest round of violence began on April 22, 627 people have been killed and some 2,900 wounded. It said the dead included 124 minors under the age of 18.

Rebels seized part of Aleppo from forces loyal to head of Syrian regime Bashar Assad in 2012, after Assad’s forces, backed by Russian airstrikes, advanced in rebel-held parts of the city in recent months.

Aleppo-based activist Baraa al-Halaby said opposition fighters in Syria’s largest city and once commercial center were not informed about the truce. He added that although there is a truce, government forces as well as Russian and Syrian warplanes have been targeting the Castello road that links rebel-held areas with the rest of the country, preventing people from leaving.

Humanitarian aid organization Mercy Corps said there has been “a significant decrease in violence, although there have been minor infringements.”

Mercy Corps expressed deep appreciation towards any opportunity to deliver life-saving aid safely and relieve the Syrian people of the seemingly endless violence of this conflict.

“However, a scant 48 hours is not enough time to ensure that the hundreds of thousands of vulnerable people in east Aleppo have the food and other essentials they need,” said Xavier Tissier, North Syria director for Mercy Corps.

Near Aleppo, fighting continued between members of the ISIS group and the U.S.-backed predominantly Kurdish Syria Democratic Forces near the ISIS stronghold of Manbij.

The U.S. Central Command said that as of Monday, the Syrian Arab Coalition completed the first phase of their operation to free the town of Manbij by securing the territory surrounding the ISIS stronghold.

“After clearing Daesh from this area they are now ready for the second phase to liberate the city itself,” the CENTCOM statement said, using an Arabic acronym to refer to ISIS. It added that since

the operation against ISIS in Manbij began in late May, the U.S.-led coalition has conducted more than 190 airstrikes in the vicinity of Manbij.