BEIRUT — The Syrian cease-fire appeared to be holding on Tuesday despite sporadic and minor violations of the U.S. and Russian brokered truce, which is aimed at paving the way for the delivery of humanitarian aid and the revival of peace talks.

The deal, hammered out by U.S. Secretary of State John Kerry and his Russian counterpart Sergey Lavrov last week, officially came into effect at sunset on Monday. The Syrian army said it would abide by the cease-fire until midnight Sunday, while maintaining its right to defend itself against any violations.

Syria’s largest insurgent groups have expressed misgivings about the deal, which allows for strikes against al-Qaida-linked militants who fight alongside the rebels. Jabhat Fatah al-Sham, an al-Qaida-linked group previously known as the Nusra Front, has denounced the agreement.

The deal marks the second attempt this year to try reduce violence in war-torn Syria, where the 5 ½ year conflict has killed more than 250,000 people and displaced half the country’s population of 11 million. A truce in late February collapsed weeks later.