Is it permissible under international law to militarily attack a country/region if it's conducting a total blockade, including of foodstuff?
Tigray (TDF) regional authorities say they are now attacking the neighboring Amara and Afar regions (which have different regional governments under Ethiopia's federal constitution) because Tigray needs to open a communications/trade route to allow aid in, which is blockaded by the federal government forces and their regional allies.
Getachew confirmed that the Tigray forces’ aim in the Afar region is to control a crucial supply line to the rest of Ethiopia from neighboring Djibouti, on a major shipping lane. He called it “part of the game,” saying people in Tigray are starving.
The UN seems to confirm that Tigray is under [near-]total blockade from the Ethiopian government, including of UN humanitarian aid--as the BBC relates:
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 tha[n] 10% of the aid supply needed.
To the south, pro-government forces in the Amhara region have been preventing supplies from getting through.
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.
This level of blockade itself may be a war crime, but is it justifiable under international law to attack a neighboring country/region in such circumstances?