The United Nations says the flow of humanitarian aid into Ethiopia's northern Tigray region has been severely disrupted with no supplies currently getting into the region.
Fighting between government and Tigray forces, as well as roadblocks on key transport routes is preventing convoys carrying food aid entering the Tigray region.
The UN says more than five million people are in dire need of humanitarian assistance.
What's stopping aid getting through?
Getting aid into areas in most need has been challenging, as the only viable overland route through the neighbouring Afar region has been put in jeopardy by TPLF attacks as well as by restrictions imposed by the regional and federal authorities.
The UN says no trucks carrying provisions have entered Tigray via this route since 22 August, and none with food aid since 20 August.
An estimated 172 trucks are now stuck at Semera, the regional capital of the Afar region.
The UN says 100 trucks a day need to cross into Tigray to meet the needs there.
However, since mid-July, only 335 trucks have made it into the region, which is less that 10% of the aid supply needed.
Grant Leaity, the UN's acting humanitarian coordinator for Ethiopia, warns that the situation is "set to worsen dramatically".
Blocking of aid convoys
To the south, pro-government forces in the Amhara region have been preventing supplies getting through.
Fighting has also spread into this region, displacing more people and making the routes insecure.
The US has accused the TPLF fighters of attacking and looting aid warehouses in the areas they have captured in the Amhara region.
It's also been impossible to bring in aid by road from Sudan, into western Tigray, an area under the control of groups supporting the Ethiopian government.
And now, with the route via the Afar region severely restricted, the problem has become particularly acute.
In a recent attempt to evaluate the route, a UN vehicle was blocked by Afar regional police and forced to turn back.
"Consequently, Mekelle-Semera movements were cancelled by the UN until further notice," according to a UN spokesman.
The UN also says delays in getting approval from government officials and multiple checks have been delaying the movement of convoys.
It says with the current procedures, only 30 trucks can be checked each day.
Billene Seyoum, a spokesperson for the Ethiopian prime minister, told the BBC that "these need not be considered as 'restrictions and numerous roadblocks' as the government has to equally ensure and guarantee security".
The head of Ethiopia's disaster relief agency, Mituku Kassa, has accused the TPLF in the Afar region of stopping aid trucks destined for Tigray.
Prime Minister Abiy Ahmed has also accused the rebels of blocking humanitarian assistance to Mekelle through the Afar region, by bombarding the road with heavy artillery.
The TPLF has denied the accusation and instead blamed the government.
"They are using conflict that is taking place in areas where there is no traffic whatsoever and he is giving all kinds of excuses and pretexts to obstruct food convoys," Getachew Reda of the TPLF told the BBC.
Foreign Affairs Minister Redwan Hussein has also accused certain, unspecified, humanitarian organisations of working to arm the TPLF, claiming the government had caught them delivering weapons and equipment to the rebels.
Doctors Without Borders (MSF) says public statements casting suspicion on aid organisations' activities are jeopardising the safety of its staff and patients.
The UN says 23 aid workers have been killed in the region since fighting broke out in November last year.
The international relief operation is also facing severe financial constraints. The UN estimates that it needs $170m in additional funding between now and December 2021.
Large parts of the region have been under a communications blackout and without electricity, affecting the delivery of key services.
"Shortages of fuel and cash, as well as a communications blackout, are significantly hindering the resumption and preventing the scale-up of humanitarian response," the UN says.
The prime minister's spokesperson, Billene Seyoum, told the BBC "resumption of these services heavily depends on the acceptance of the belligerent group [the TPLF] to a ceasefire."