United Nations aid chief Martin Griffiths said on Thursday it was unlikely the Black Sea grain deal would be expanded in the near term to include more Ukrainian ports or reduce inspection times.

Kyiv has called for an expansion of the deal with Moscow which was mediated by the United Nations and Turkey and allows Ukraine, a major global grain exporter, to ship food products from three of its Black Sea ports despite Russia’s invasion.

“I don’t see that happening in the next, near term,” the U.N. under-secretary-general for humanitarian affairs and emergency relief coordinator told Reuters in an interview in the Ukrainian capital.

“I think it would be great if it could be expanded, the more grain that gets out into the world, the better clearly from our point of view, from the world’s point of view. But I don’t think that’s immediately likely.”

Griffiths travelled to Ukraine this week, visiting the southern cities of Mykolaiv and recently liberated Kherson as Ukraine grapples with winter power outages caused by Russian air strikes on critical infrastructure.

The official, who said he was not in Ukraine to mediate and that he was strictly there to review the humanitarian aid program, said on Nov. 30 that a deal was “close” to agreeing a resumption of Russian ammonia exports via Ukraine.

Ammonia, which is used to make fertilizer, would be pumped through an existing pipeline to the Black Sea. The pipeline was shut down when Russia invaded this year.

On Thursday, Griffiths said work on that agreement was still under way and that he did not know when it would go through.

“We continue to… obviously want it because … fertilizer at the moment is almost more important than grain in terms of export to the global south,” he said. “So we’re still working at it. I don’t know when it will go through.”

Russian and Ukrainian representatives have discussed the possibility of linking a prisoner swap that would release a large number of prisoners on both side to the resumption of ammonia exports.

Rebeca Grynspan, Secretary-General of the U.N. Conference on Trade and Development, voiced optimism earlier on Thursday that there would be a breakthrough in negotiations.

At a news conference earlier on Thursday with Ukraine’s prime minister, Griffiths said international humanitarian aid agencies had reached just under 14 million people with assistance since the beginning of the war.