Residential areas and refugee camps are coming under fire amid the fighting in Yemen, the country’s foreign minister said.
Ahmed Awad bin Mubarak accused the Iran-backed Houthi rebels of boycotting and undermining efforts to bring about peace.
He spoke on a visit to Berlin where his German counterpart Heiko Maas said that the peace process was at a stalemate.
Both ministers voiced concern over the recent Houthi offensive in the Marib region.
“What we are experiencing in Marib is an unprecedented escalation of the crisis,” said Mr Mubarak.
“We have two million displaced people, and if the crisis in Marib should intensify, then it would be a particularly awful humanitarian catastrophe.”
Mr Mubarak said that civilians were coming under fire in the port of Hodeidah and elsewhere in Yemen, including at refugee camps.
He also said the Houthis were leaving Yemen vulnerable to an “environmental catastrophe” by foiling efforts to rescue an oil tanker from the Red Sea.
More than a million barrels of oil are at risk of leaking into the sea from the stranded FSO Safer, it is feared, but a rescue trip has been repeatedly delayed.
“The Houthis have behaved in a particularly irresponsible way in regard to this oil tanker”, Mr Mubarak said.
“We will engage positively with every initiative in the region or internationally so that we can get back to the negotiating table and set out a clear roadmap.”
Mr Maas said the humanitarian situation could worsen because of a lack of funding for aid programmes.
There are similar fears in Jordan, which says that a lack of donations during the pandemic has left Syrian refugees in a perilous situation.
A UN aid plan for Yemen has only about 43 per cent of the funds it needs, and money for humanitarian assistance could run out by the end of August, Mr Maas said.
He said Germany had offered an extra €200 million ($237m) of aid, but that other donors were providing less funding than should have been expected.
“This is a situation that can’t continue, and in addition to what we’re providing, we urge others who can to commit more,” he said.
“Otherwise, there will be even worse developments in what is already a humanitarian crisis, a humanitarian disaster.”
Mr Maas said Germany was following the Marib offensive with growing concern.
“Thousands of families are being displaced yet again because of the combat operations”, he said.
“It makes it more urgent that we have a ceasefire to make humanitarian aid possible.”
However, he said that there was too much stalemate in the political process in the seventh year of the conflict in Yemen.
The war erupted in 2014 when the Iran-backed Houthis seized the capital Sanaa, forcing the internationally recognised government into exile.
The conflict has killed more than 130,000 people and triggered the world’s worst humanitarian crisis.
A UN peace plan calls for a ceasefire, the re-opening of Sanaa airport and a regular flow of fuel and other goods into Hodeidah.
Mr Maas said the ongoing nuclear talks in Vienna between Iran and world powers could eventually lead to a discussion on Yemen.
He said Germany wanted to discuss how to break open the Yemen peace process and “finally start to make progress again.”
“We owe it to the Yemeni population, who have suffered too much for too long”, he said.
“There are plenty of proposals for a return to the political process. There are more and more attempts at mediation, internationally and regionally, and several formats for dialogue.
“But in the end, it’s also up to the parties to the conflict to take up these offers.”