Ukrainian President Volodymyr Zelenskyy and Dutch Prime Minister Mark Rutte, visiting the Black Sea port of Odesa, vowed on Friday to improve Ukraine’s air defenses and to increase the security of a “humanitarian corridor” for grain exports.

Zelenskyy said Kyiv was working to strengthen its position in the Black Sea so that it can continue grain exports, which are vital to ensuring budget revenues following a surge in defense spending after Russia’s invasion last year.

“We are working with partners to protect properly these corridors, and strengthen our positions in the Black Sea, and it also applies to the protection of Odesa’s skies and in the region as a whole,” he told a joint press conference alongside Rutte.

Ukraine’s government outlined details of Russian attacks on infrastructure and the results of the alternative “humanitarian” corridor organized by Ukraine since Russia abandoned a U.N.-backed accord on safe Black Sea grain shipments in July.

It said Russia has destroyed almost 300,000 metric tons of grain since July in attacks on Ukraine’s port facilities and on ships. Russia’s Defense Ministry did not immediately respond to a request for comment on Ukraine’s allegations.

Deputy Prime Minister Oleksandr Kubrakov said that since the deal ran out, Russian forces had hit six civilian ships and 150 port and grain facilities during 17 attacks, destroying crops headed for export.

Kubrakov said 21 grain-loaded vessels had already used the new grain corridor.

The Odesa region has came under frequent Russian missile and drone attacks. Zelenskyy and Rutte visited a damaged port.

Rutte said the Netherlands would provide more Patriot air defense missiles to help Ukraine defend itself in the winter. The Netherlands would also help Ukraine acquire patrol boats, he said, to help keep the grain export route safe.

The Netherlands has provided Ukraine with financial aid and weapons during the war and has led efforts to help train Ukrainian pilots on F-16 fighter jets.

Ukraine’s humanitarian corridor was initially announced to release ships that do not carry grain, were not covered by the grain deal and had been trapped in port for more than a year, but vessels seeking to load grain have also used the corridor.

Zelenskyy also said Ukraine was nearing an agreement with some partners on insurance for ships using the corridor but gave no details.