"It's sometimes impossible to reach people in need, because of the complete lack of security," Michel Masson, head of the ICRC delegation in Ukraine, said in a statement, published on the ICRC's website Tuesday.
Masson noted the deteriorating situation in the region, with the city of Debaltsevo in particular at the forefront of increased clashes over the past few days. Western portions of the town, a key rail and road juncture, are claimed to be under local militia control.
"People are hiding in basements for days on end and those who dare to venture out to collect basic aid risk being wounded or killed," Masson added.
Earlier on Tuesday, the UN High Commissioner for Human Rights released updated figures of civilian losses that the conflict has brought about.
"The death toll now exceeds 5,358 people, and another 12,235 have been wounded since mid-April last year. In just the three weeks up to February 1, at least 224 civilians have been killed and 545 wounded," Zeid Ra'ad Al Hussein said.
In April 2014, Kiev launched a military operation against predominantly Russian-speaking independence supporters in east Ukraine, following opposition to a coup-imposed Ukrainian government that seized power in February.
Shelling and mortar attacks intensified recently despite a ceasefire agreement reached in the Belarusian capital of Minsk in September 2014.
