Yemen‘s warring parties are refusing to discuss U.N.-brokered peace efforts, the United Nations‘ envoy for the country said on Tuesday, amid an escalation in violence that he said was having a “dramatic” impact on the civilian population.

At least 10,000 people have been killed in nearly two years of war between a Saudi-led Arab coalition and the Iran-allied Houthi movement. Already desperately poor even before the war, Yemen is now in the throes of a major humanitarian crisis.

“We know today that a solution is close because we know it. We know that a solution in Yemen will be based on a military and political aspect so it‘s a bit of a shame that the parties don‘t want to sit down at the table to discuss that,” U.N. envoy Ismail Ould Cheikh Ahmed told reporters after talks in Paris with French Foreign Minister Jean-Marc Ayrault.

“One of the subjects that concerns us the fact that we‘re seeing an increase in military operations with the consequences which that is having on the civilian population,” Ahmed said.

Saudi Arabia intervened in Yemen‘s civil war in 2015 to back President Abd-Rabbu Mansour Hadi after he was ousted from the capital Sanaa by Houthi forces.

While government forces in the south and east nominally hold most of Yemen‘s territory, Hadi has struggled to enforce state authority among various militias, militants and tribes.

The Houthis control most of Yemen‘s population centres in the northwest, including Sanaa. Army forces and a group of militias called the Southern Resistance launched an offensive on the Red Sea coast this month to deprive the Houthis of ports and to isolate them in the inland capital.

Some 7.3 million Yemenis are now classed by the U.N. as “severely food insecure”, while there has been an upsurge in civilian casualties as bombing and fighting intensify.