US Secretary of State John Kerry said he expected more aid deliveries to reach civilians in Syria on Monday but it remained to be seen if a ceasefire would hold.
The ceasefire "did pretty well last night, trucks are moving to maybe eight locations or more" to deliver aid, Kerry told reporters as he met Tunisia's foreign minister in New York.
"Let's wait," he said, on the sidelines of the UN General Assembly meeting.
Russia's defense ministry appeared to bury the week-long ceasefire brokered with the United States, saying rebel violations made it "pointless" for government troops to uphold the truce.
After months of negotiations, the United States and Russia reached the agreement on September 9 that calls for a ceasefire, the delivery of aid and the joint targeting of Islamist rebels in Syria.
The ceasefire ran into trouble at the weekend when rebel-held districts of Aleppo came under a barrage of air strikes and the US-led coalition killed dozens of Syrian soldiers in a strike that Washington said was unintentional.
A senior military source in Damascus told AFP that the truce would expire later Monday at 7:00 pm (1600 GMT) if no extension was announced.