LISBON: Ukrainian President Volodymyr Zelenskyy received a second $1-billion promise of military aid in as many days on Tuesday during a whirlwind tour of three European Union countries, even as President Vladimir Putin warned that hitting Russian soil with Western-supplied weapons could set the war on a dangerous new path.

The aid pledge for 2024 came from Belgium, which topped up the money with a commitment to give Ukraine 30 F-16 fighter jets in the next four years.

“Our task is to use the first F-16 on the battlefield this year and in such way that it will fortify our positions,” Zelenskyy said.

He later travelled to Portugal, where he said it was important that Ukraine’s supporters don’t allow themselves to be misled by Russia and that “we don’t grow tired of the war”.

Slow deliveries of support by its Western partners, especially a lengthy delay in military aid from the United States, have left Ukraine at the mercy of Russia’s bigger army and air force.

European countries have been discussing the possibility of deploying troops to Ukraine in support roles, while talk of giving seized Russian assets to Ukraine has further angered Moscow.Putin has repeatedly warned the West against deeper involvement in the fighting, holding out the spectre of a nuclear conflict.The use of Western-supplied long-range weapons by Ukraine to strike Russian territory could bring a dangerous escalation, Putin said on Tuesday, speaking to reporters while on a trip to Uzbekistan.

The use of such weapons would rely on Western intelligence data and imply the involvement of NATO military personnel, Putin said, warning the alliance that they should be aware of the possible consequences.

The Netherlands promised to quickly assemble with key EU partners a Patriot air defense system, which Zelenskyy sees as key in stopping Russia from hitting Ukraine’s civilian areas, as well as military targets, with devastating glide bombs.

Before returning to Ukraine, Zelenskyy visited Portugal and signed another bilateral agreement. Prime Minister Luis Montenegro said Portugal is sending a further 126 million euros ($137 million) in military and financial aid to Kyiv as part of a broad cooperation plan.

On Monday, Zelenskyy had signed a security agreement with Spain that allocates 1 billion euros ($1.1 billion) of military aid to Ukraine in 2024, and 5 billion euros ($5.4 billion) by 2027.