Ukraine leader Volodymyr Zelensky called Monday on the West to "use all means" to force Russia to peace talks during a visit to Madrid, which pledged one billion euros in military aid as a Russian offensive gained new ground.

The visit came as NATO chief Jens Stoltenberg urged Ukraine's allies to rethink their restrictions on Kyiv usng Western weapons to strike inside Russia, a key demand of the Ukrainian president.

"We need to intensify our joint work with our partners to achieve more. Security and tangible coercion of Russia to peace by all means," Zelensky told a joint press conference with Spain's Prime Minister Pedro Sanchez.

Russia meanwhile announced it had captured two more villages in eastern Ukraine, the lastest in a series of gains in recent weeks. Ukraine said that France would soon send military instructors.

On the back foot, Ukraine has been pressing its backers -- especially the United States -- to allow it to use longer-range weapons they supply to hit targets inside Russia.

Washington and other allies have been reluctant to permit Kyiv to strike over the border out of fear that it could drag them closer to direct conflict with Moscow.

Zelensky pressed home the point in Madrid.

"We need to work together and put pressure not only on Russia, but also on our partners to give us the opportunity to defend ourselves against Russia," Zelensky said.

"Even those partners who are afraid to give this or that advice should understand that air defence is defence, not attack," reiterating his call for aerial defence systems capable of intercepting the 3,000 aerial bombs hitting Ukraine each month.

There are signs of a Western rethink.

Stoltenberg told NATO lawmakers in Sofia on Monday that the time had come to reconsider lifting those restrictions.

"If (Ukraine) cannot attack military targets on Russian territory then it ties one hand of the Ukrainians on their back and makes it very hard for them to conduct defence."

On Sunday, however, Italy's Prime Minister Giorgia Meloni opposed giving Ukraine greater flexibility on Russian targets. "I think we have to be very careful," she told Italian television.

Earlier this month, British Foreign Secretary David Cameron said during a visit to Kyiv that Ukraine had every right to use British-donated missiles to strike inside Russian terrority.

Questioned on Monday, Sanchez was evasive, saying he "had no such desire".

"We will be at Ukraine's side for as long as it takes," Sanchez said, announcing a military aid package as part of a security pact "to enable Ukraine to strengthen its defence capabilities."

 Patriots needed  

Ukraine is calling for US Patriot air defence systems to counter Russian bombardments, arguing that it has only a quarter of the resources it needs.

In Madrid, Zelensky said he needed "seven additional Patriot systems," including "at least two for Kharkiv," which is close to the Russian border and is being regularly shelled.

Sanchez said Spain had already sent Patriot missiles to Kyiv, and is "working with various allied countries to see exactly" how many more launchers can be sent.

In a separate effort, French military instructors would soon arrive in the war-battered country, Kyiv's army chief Oleksandr Syrsky said Monday

"I have already signed the documents that will allow the first French instructors to visit our training centres soon and get acquainted with their infrastructure and personnel," Syrsky said on social media.

 Russians take two more villages 

 Less than three weeks before a Ukraine peace summit in Switzerland, Zelensky ruled out proposals by China and Brazil to invite Russia "because Russia will block everything."

Zelensky had been due to visit Madrid on May 17, but postponed his trip after Russian troops began a major assault on the Kharkiv region.

Russia on Monday claimed to have captured two more villages in eastern Ukraine, where a strike on a hypermarket in Kharkiv, the country's second-largest city, killed 16 people on Saturday.

A new strike on an industrial zone in the city killed a woman on Monday, authorities said.

A separate Russian attack on the village of Snigurivka in the southern Ukrainian region of Mykolaiv left three dead, including two teenagers, and wounded six more, the regional governor said.