Former British Prime Minister Boris Johnson said the United Kingdom and its allies need to supply Ukraine with aircraft to take out drones.

Johnson, during an interview with CNN, discussed Ukraine's efforts in fighting Russia, which began an unprovoked invasion in February.

"We [need] to supply them with better artillery, but we also, frankly, should be giving them, not just helicopters, but fixed-wing aircraft that can go fast enough to take out the drone," Johnson told CNN's Richard Quest.

"And you don't need very sophisticated planes to do this. The Ukrainians came to see me about it. You can do it with spitfires. We don't make spitfires anymore. But you just need a plane that can go a few hundred miles an hour."

Earlier this month, the Biden administration rejected pleas from Ukraine and a bipartisan group of U.S. lawmakers to supply President Volodymyr Zelenskyy's military with advanced drones.

Pentagon officials were worried that Russian President Vladimir Putin would see a supply of drones as a sign the U.S. was providing weapons that could target positions inside Russia, officials told The Wall Street Journal.

Johnson, however, said more can be done to help Ukraine defend itself without appearing to enhance offensive capability.

Johnson, speaking to Quest at an event for CNN Portugal, was asked how he would justify continuing to support Ukraine if the rest of Europe experiences a harsh winter without the usual energy supplies from Russia.

"Well, you come to very, very influential audiences in places like Lisbon, and you try to get your message across because I agree with you – it's going to be a tough one," Johnson told CNN.

Ukrainians themselves braced for a winter with little or no power in several areas, including Kyiv where temperatures already have dropped below freezing as relentless Russian strikes crippled the country's energy capacity.

"I happen to think the Ukrainian resolve is being strengthened by the attack on their infrastructure," Johnson told CNN. "Remember what happened to London in the blitz. It didn't lead to a collapse of morale. On the contrary, morale was stiffened by the aerial bombardment."

Reuters contributed to this story.

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