Ukraine needs more air defences to protect its grain export routes as well as regions bordering Russia, President Volodymyr Zelenskiy said on Saturday, as he addressed an international summit on food security in Kyiv.

"There is a deficit of air defence - that is no secret," Zelenskiy told the Grain from Ukraine summit, which was attended by senior officials from European countries, including Swiss President Alain Berset and Lithuanian Prime Minister Ingrida Simonyte.

Zelenskiy was speaking after Russia attacked Ukraine with 75 drones overnight, the biggest drone assault of the war. The joint press conference of the three leaders was cut short by another air raid siren.

Zelenskiy said Ukraine would be supplied by its foreign partners with vessels to accompany convoys of cargo ships from Ukraine's ports to guarantee their security.

"I have agreements with several countries about powerful accompaniment of convoys by Ukrainians, but using (foreign) equipment," he said.

Separately, European Commission President Ursula von der Leyen pledged support in a letter to Zelenskiy that she shared on social media platform X, saying the Commission would make available 50 million euros for "quick repairs and upgrades of infrastructure in Ukraine's ports."

The Ukrainian president said Kyiv hoped to solve its air defence shortage through new supplies from partners and increasing its own production capacity, something on which he said there had been progress.

"As of today, I can't say details what we are making and where, but there is progress," he said.

Ukraine, a major exporter of grain, has been exporting grain via unilateral corridors through the Black sea, after Russia withdrew in July from a UN-brokered deal to allow grain ships through its blockade.

Ukraine's current Black sea grain export corridors all start from ports in Ukraine's southern region of Odesa.

"There are certain air defence systems... we are asking for them," Zelenskiy said. "We've already got an answer when those systems will start to guard that region. Because there, both the corridor and the people are important."

Asked about the protests by Polish and Slovak truckers which have blocked much of Ukraine's road-based cargo supply in recent days, Zelenskiy blamed the problem on the internal politics of those countries.

"I believe that there are difficulties on the border first and foremost because of certain political steps by our neighbours," he told a press conference after the summit.

Zelenskiy said he was confident the issue would be solved if Ukraine's neighbours were given "a bit of time" to deal with the dispute.