The UN hails significant reduction in violence over the first 24 hours of a new ceasefire brokered by the US and Russia.

Aid convoys are waiting at the Turkish-Syrian border for the government in Damascus to give authorisation to enter Syria, the United Nations has said, as a fragile ceasefire that came into effect at sundown on Monday appeared to be largely holding across the country.

The UN envoy for Syria on Tuesday applauded the “significant drop in violence”, more than 24 hours after the declaration of a truce deal brokered by US and Russia.

“Today, calm appears to have prevailed across Hama, Latakia, Aleppo city and rural Aleppo and Idlib, with only some allegations of sporadic and geographically isolated incidents,” Staffan de Mistura told a news conference in Geneva.

“Sources on the ground, which do matter, including inside Aleppo city, said the situation has dramatically improved with no air strikes,” he said.

Twenty-four hours after the tentative ceasefire took effect, the UK-based Syrian Observatory for Human Rights said that it had received not a single report of combatants or civilians killed by fighting in any areas covered by the truce.

“This is so far the most successful ceasefire to take place in the country,” the Syrian observatory’s Rami Abdulrahman told Al Jazeera on Tuesday.

The truce deal does not apply to the Islamic State of Iraq and the Levant (ISIL), or Jabhat Fateh al-Sham, the group formerly known as al-Nusra Front that changed its name after cutting ties with al-Qaeda in July.

The truce agreement has been accepted by the Syrian government and, far more reluctantly, by most of the groups that oppose it, with rebel forces saying that the deal was skewed in favour of President Bashar al-Assad.

Russia said Syrian government forces were fully respecting the ceasefire but that rebel fighters had violated it 23 times.

“Syrian government troops have completely stopped firing, with the exception of areas where the Islamic State [ISIL and Jabhat Al-Nusra fighters are active,” senior Russian military officer Viktor Poznikhir said in a televised briefing.

‘Aid trucks waiting’

Speaking to reporters, de Mistura dismissed earlier reports by Turkish state media that aid lorries on Tuesday had entered Syria heading towards rebel-held eastern Aleppo, saying that the UN was still waiting for authorisation from the government in Damascus.

“We are asking them to issue them very quickly so that … we can take advantage of this reduction of violence in order to be able to make sure that, not only eastern Aleppo, western Aleppo but everywhere else, convoys can start moving,” he said.

“We have not yet received those authorisation letters but we are eagerly hoping and expecting the government to issue them very soon.”

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De Mistura also said that UN officials were awaiting assurances that the aid convoys would be “unhindered and untouched” after crossing from Turkey into Syria.

“We are waiting for this cessation of hostilities to actually deliver the assurances and the peace before trucks can start moving from Turkey. As I speak, that has not been the case,” Jens Laerke, spokesman for the UN Office for the Coordination of Humanitarian Affairs, also said in Geneva on Tuesday.

“We need to enter an environment where we are not in mortal danger as humanitarian organisations delivering aid.”

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The Syrian government said it would reject any aid deliveries to Aleppo not coordinated through itself and the UN, particularly from Turkey.

The Syrian foreign ministry said: “Commenting on the statement issued by the Turkish regime on its intention to send what it says is humanitarian aid into Aleppo, the Syrian Arab Republic announces its rejection of the entry of any humanitarian aid to Aleppo, particularly from the Turkish regime, without coordination with the Syrian government and the United Nations.”

Turkey said it was already making preparations to deliver humanitarian aid to Aleppo, where some 250,000 people in the rebel-held east are under government siege.