DAMASCUS —The siege of Madaya and the shocking images of starving children have brought renewed global attention to the Syrian conflict, and especially the widespread use of siege tactics.

Over the past several weeks, the factors and events that led to some two dozen people starving to death in Madaya have become clearer. The situation has also illuminated the mechanics of modern sieges and highlighted the limited ability humanitarian agencies have to address them.

When reports started to surface in November that people were starving to death, Syrian officials issued blanket denials. The state-run SANA news agency called the reports "falsification and disinformation."

Allies of President Bashar al-Assad followed suit in the international press, working to mock and discredit photos of the starving children and suggesting the situation was being exploited as "Western propaganda."

Tucked away in the Qalamoun mountains of rural Damascus, Madaya is surrounded by a natural valley on three sides. Residents joined protests in the summer of 2011, marching through its small streets chanting for political freedoms and flying the flag of the revolution in the town square.

In 2013, as protests turned to civil war, the Syrian Arab Army (SAA) began tightening its control over movements in and out of the valley where Madaya and Zabadani are nestled. A single road toward the border with Lebanon leads through the area where, for a time, many Syrians passed through on their way to safer ground in Lebanon. This made Madaya a target for the army, forcing rebels to rally to fight for control of the border area.

When supplies stopped

The government enacted a total blockade in July, shutting down the road to Damascus while its ally Hezbollah encircled the valley from the Lebanese side. Checkpoints were set up on the only road in or out, and mines were planted in the area.

Violence intensified throughout the summer, as government airstrikes in neighboring Zabadani sent 20,000 people fleeing to Madaya, doubling its population and prompting the first appeals for support from the outside world. With regular commerce suspended, food and medical supplies steadily dwindled.

Hunger and cold set in throughout the fall. From August through November, Madaya activists posted photo after photo counting the days of the siege. A delivery of emergency food aid came in October — the first in three months — but it was more of a painkiller than a cure. Inundated with dozens of cases of fainting every day due to lack of food, doctors had to improvise crude IV drips out of leftover kitchen supplies. By December's end, 23 people had died of starvation.

By November, there were already reports of deaths by starvation, inflated prices and claims of hoarding food and supplies. Yet people in Madaya could do little but hold small protests continuing their appeals for the world to intervene. It wasn't until Jan. 7, after dozens of starvation deaths and a chorus of international outcry, that the United Nations announced its plan to intervene.

Humanitarian organizations operating inside Syria were harshly criticized for their failure to save lives in the besieged town. Just 15 miles from their offices in Damascus, they could have reached Madaya in under an hour.

Almost impossible to reach

"Syria is not an easy country to work in," Red Cross spokesman Pawel Krzysiek responded. Even when they know there is a critical need for assistance, humanitarian organizations must obtain permission from several government ministries to cross army checkpoints and deliver the aid. "There are a lot of administrative procedures. You have to constantly negotiate access, link with multiple actors on the ground or in the skies, get permission and agreement of all parties, and security guarantees."

Iyad Nasr, spokesperson for the UN's humanitarian branch, said they had asked that the Syrian government allow them access into Madaya seven times over the past year. "We simply were not given permission to cross the checkpoints and to actually get into Madaya until very recently," he said.

The opposition fighting the Assad government has for years accused the army of targeting besieged cities with a campaign they call "Kneel or Starve." At least 450,000 people are living under siege in Syria, according to the UN, although other watchdog organizations estimate the number could be as high as 1 million.

The tactic has been used by government troops, rebel groups and ISIS. A 2014 inquiry by the UN Human Rights Council found such limitations of movement to be common practice inside Syria. "Partial sieges aimed at expelling armed groups turned into tight blockades that prevented the delivery of basic supplies, including food and medicine, as part of a "starvation until submission" campaign," the report said. "In blatant violation of international law, civilians are generally not allowed to leave the besieged areas and may be killed or arrested for trying to do so."

UN human rights official André-Michel Essoungou said maintaining a siege requires a high degree of control over entry and exit points "and is primarily enforced by installing checkpoints."

A paramedic working with the rural Damascus branch of the Syrian Arab Red Crescent and who spoke on the condition of anonymity said that even marked ambulances can't pass freely through checkpoints outside of Damascus without advance authorization — even in emergencies.

Humanitarian missions by international groups require an even higher level of approval. Stephen O'Brien, OCHA's top official, confirmed that negotiating permission from the government has stymied efforts to get through to hard-to-reach areas.

"Only 23 of 85 convoy requests made by the UN have been approved in principle by the Syrian minister of foreign affairs," O'Brien said, referring to the 2014-15 reporting period. "Less than half of those approved actually were carried out due to lack of final security clearances and lack of safe passage."

Yet civil society opposition figures say the UN is waiting for permission it does not need according to international law. They charge that its inability to push the government to allow humanitarian access has left cities like Deir Ezzor besieged both by ISIS and by the government's army, which continues to use the region's airport for bombing missions and refueling but denies access for humanitarian purposes.

Still, army-controlled checkpoints remain the reality. Humanitarian workers cannot just go around them, and have little choice but to be pragmatic. "There is a lot of public condemnation toward everyone, but if you want to work in Syria, you have to gain trust and remain neutral to the conflict," Krzysiek said. "Sometimes we fail, but we have to always keep pushing for access."

The story of Madaya isn't unique. While the world remains uninformed of their plight, or stalling in disagreement over who's to blame, hundreds of thousands of Syrians remain blockaded by besieging forces. Separating the facts from the agendas is a difficult but necessary first step to understanding and addressing the conflict.