Syria has given approval for humanitarian convoys to reach all of the country's besieged areas by the end of this month, the United Nations has said, but warned that "approval ... does not mean delivery".

Nearly 600,000 people are besieged in 19 areas in Syria, with two-thirds trapped by government forces and the rest besieged by armed opposition groups and the Islamic State of Iraq and the Levant (ISIL, or ISIS) group.

Syrian army and Kurdish fighters racing for Raqqa control

"We were informed by our team in Damascus that basically there has been a permission, an approval ... by the government of Syria for all 19 besieged areas," the UN envoy to Syria, Staffan de Mistura, said on Thursday.

But, he stressed that Syria has given such approvals in the past before ultimately blocking convoys from distributing life-saving supplies.

READ MORE: UN to ask Syria permission to airdrop aid

The Syrian government has previously turned down five out of 34 requests in June to deliver aid to 19 besieged areas by land convoys, according to the UN. 

"We were hearing earlier this week that only 17 of the 19 besieged areas had actually received approval," said Al Jazeera's Andrew Simmons, reporting from Gaziantep.

"It's certainly is the case that Stefan de Mistura has made warnings in the past, tried to put pressure on the Syrian government to give way on this issue of aid reaching all of the 19 besieged areas in Syria," he said.

"However, it really is a case of what he describes as approval. It does not necessarily mean delivery."

READ MORE: Deadly air strikes hit Aleppo hospital

Mistura made his latest comments about the Syrian government's approval for aid delivery convoys after the weekly meeting of the Syria humanitarian task force, co-chaired by the US and Russia, which has for months been trying to boost aid supplies to millions of Syrians in need. 

That task force has faced pressure, including from France and the UK, to start airdropping aid into besieged areas, with Syrian President Bashar al-Assad's military continuing to block road convoys.

Last week, during a closed-door meeting of the Security Council, diplomats said they will be asking permission from the Syrian government to airdrop aid packages in besieged areas and described airdrops as a "last resort" to reach thousands of civilians in need of aid.

READ MORE: US drops weapons to rebels battling ISIL in Syria

But, on Thursday, Mistura said "all options are on the table", voicing hope that a surge of road convoys in the coming weeks would make dangerous and costly air deliveries unnecessary.

Bashar Jaafari, Syrian ambassador to the UN, on the other hand, previously rejected accusations that the government has ever been preventing aid deliveries in besieged areas.

"Humanitarian assistance or the humanitarian aid has never been denied by the Syrian government to any part of the country," he told reporters at the UN headquarters in New York.

Syria's conflict started with mostly unarmed demonstrations against President Bashar al-Assad in March 2011.

It has since escalated into a full-on civil war that has killed at least 270,000 people, according to the UK-based Syrian Observatory for Human Rights.

WATCH: Aid agencies struggle to reach besieged towns in Syria


Source: Al Jazeera and agencies