Millions of people in Yemen need help following a week of deadly clashes and air strikes.
Medical and food supplies are running low and efforts to reach people with aid are being hampered by the on-going violence.
The fighting has left hundreds dead and many more injured.
The Red Cross has also condemned the killing of Yemeni Red Crescent volunteer, Omar Ali Hassam, who was shot dead while helping wounded people on Monday.
“The numbers affected are staggering. We can get help to people, but we need support.
“While violence in Syria and Iraq has dominated headlines of late, the situation in Yemen has gone largely unnoticed.
“There are severe humanitarian needs and it’s vital that aid is allowed to reach those Yemenis who desperately need it.”
There have been reports of civilian casualties following air strikes in the capital Sana’a and other parts of the country.
Efforts to deliver emergency aid have been restricted by the violence.
Yemeni ports are closed and attempts to negotiate the arrival of a plane-load of Red Cross medical supplies have so-far been unsuccessful.
The supplies are needed in hospitals across the country, which are running low on resources.
“There are casualties across the country,” said Cedric Schweizer, head of the ICRC in Yemen.
“There have been air strikes in the north, west and south, and clashes between opposing Yemeni armed groups in the centre and south. These are putting immense strain on already weak medical services.
“In order that the wounded get the treatment they deserve, it’s essential we deliver urgent medicines and surgical kits.”
Red Cross response
Recent air strikes and heavy ground combat come on top of years of conflict and drought.
Much of the population is struggling to find basic health, food and water supplies.
The ICRC has helped reopen a hospital in Aden and provided medical supplies to treat war-wounded patients.
Medical centres in the southern provinces of Taiz, Lahj and Al Dhalea have also received Red Cross support.
In the northern province of Saada, the situation remains extremely tense with continued air strikes.
The ICRC has supplied medicine to the Al Munabeh hospital and the city’s Al Jomhouri hospital, which has been receiving a steady stream of patients.
Air strikes across Sana’a have continued, straining the capital’s medical services.
In response to the Al-Hoshoosh and Badr mosque bombings in the city on 20 March, which killed at least 140 people and injured 340, the ICRC provided medical supplies to the three hospitals dealing with most of the casualties.