International humanitarian groups said on Tuesday (April 14) they had sent emergency relief through overland routes to Iran, some of their first deliveries of aid since U.S.-Israeli strikes began in late February.

Aid workers say needs are high in the wake of six weeks of strikes, but stocks of emergency humanitarian supplies became stuck in Dubai warehouses as shipping and air routes were blocked by the expanding conflict.

Iranian authorities say more than 3,000 people have been killed in Iran during the war and the U.N. refugee agency says up to 3.2 million have been displaced.

The International Federation of Red ​Cross and Red Crescent Societies said it had delivered some 200 trauma kits as well as tents and blankets on trucks sent along a new route from Turkey.

The trucks crossed the Iranian border on Sunday (April 12) and are set to arrive in the capital Tehran on Tuesday, said IFRC spokesperson Tommaso Della Longa.

"For us it's very important as it represents a new route for getting aid into Iran and we're very optimistic to scale up," he told a Geneva press briefing.

"Before it was very easy to take a flight or a boat and bring aid directly to Iran in a couple of hours."

Separately, the International Committee of the Red Cross said it had made its first shipment to Iran since the conflict began, with five trucks arriving from Jordan on Monday (April 13). Another nine are expected later this week.

It also handed supplies to the Iranian Red Crescent, the only humanitarian group working across Iran, with 100,000 responders, four of whom have been killed in the war.

The ICRC trucks contained supplies like buckets, blankets and mattresses to meet the needs of some 25,000 people, including those displaced by the conflict.

Following the collapse of weekend negotiations to end the war, sources told Reuters that negotiating teams from the U.S. and Iran could return to Islamabad this week to resume talks.

Production: Cecile Mantovani/Reuters