Russia has pledged a tough response to what it calls increased US involvement in the conflict.
In a televised address to his top security officials, Putin said Russia needed to start manufacturing missiles that were previously banned under a now-defunct Cold War treaty.
He said the US had recently sent midrange missiles -- able to strike targets at a distance of 500 to 5,500 kilometres (300-3,400 miles) -- to Denmark for training exercises.
"We need to react to this and make decisions about what we should do next in this area. It seems that we need to start producing these strike systems," Putin said.
"And then, based on the reality of the actual situation, make decisions about where to deploy them for our security," he said.
Such missiles, capable of carrying nuclear warheads, were previously banned under the Intermediate-Range Nuclear Forces (INF) Treaty, but Washington terminated the deal in 2019, blaming Russia for not complying with its terms.
At the time, Putin said Russia would stick to a production moratorium.
- 'Direct confrontation' -
Russia has repeatedly warned Washington and the West they risk becoming "direct participants" in the Ukraine conflict by supplying Kyiv with weapons.
Earlier this week, Moscow summoned US ambassador Lynne Tracy to warn of "consequences" after it alleged the United States had programmed and provided data for the missiles that targeted Crimea, the Ukrainian territory annexed by Russia in 2014.
US officials have rejected the accusations and said Ukraine makes its own military decisions.
Russia's defense ministry said Friday that it had "observed an increased frequency of US strategic unmanned aerial vehicle flights over the waters of the Black Sea" that surrounds Crimea.
It said the drones were "carrying out reconnaissance" to help Kyiv use Western-supplied weapons on Russian targets.
Such actions "increase the risk of a direct confrontation" between NATO and Russia, it said, adding that the military would prepare an unspecified "operational response".
The United States routinely carries out drone flights over the Black Sea, which it says are conducted in neutral airspace and in accordance with international law.
Adding to tensions, a Ukrainian drone struck a petrol depot in central Russia early Friday, authorities said, the latest in a series of targeted strikes by Kyiv on Russia's energy infrastructure.
- Russian advances -
In Ukraine, where Moscow has made creeping gains across the front lines this year, Russian troops captured the village of Rozdolivka, around 20 kilometers north of Bakhmut, according to the Russian defence ministry.
Ukraine has suffered months of ammunition shortages, hampering its ability to defend itself on the battlefield, but on Friday soldiers said the situation was improving.
"It's become better over the past month and it keeps getting better, at least for 155mm calibre artillery shells," a Ukrainian sergeant using the call sign "Luntik" told AFP.
He said his unit was previously allowed to fire only "six shells every 24 hours", but that was now "up to 40 per day".
Russian shelling near the front line in the east and northeast killed at least five people in the Donetsk region, authorities said.
In Ukraine's northeastern Kharkiv region, where Moscow launched a major ground assault in May, Russian shelling in the morning killed a 56-year-old woman in a border village, the interior ministry said.
One person was killed and five wounded in an early evening rocket strike on an apartment block in Dnipro, the interior ministry said, adding that people were still trapped under the rubble.
A Russian rocket attack injured eight in another strike on a residential building in the Kharkiv region, the local governor said.
- Peace plan -
With no let-up in the fighting, Ukraine's President Volodymyr Zelensky said Friday that he was drawing up a "comprehensive plan" for how Kyiv believes the conflict should end.
No public talks are ongoing between Ukraine and Russia, and based on public statements the two sides appear as far apart as ever over the terms of a potential peace settlement.
But Zelensky is pushing on the diplomatic front to rally support for Ukraine's position, after an international summit in Switzerland earlier this month.
"It is very important for us to show a plan to end the war that will be supported by the majority of the world," Zelensky said Friday, adding that it should be ready in the coming months.
The official Paris Olympics sculpture by American artist Alison Sarr celebrates 'diversity' © JULIEN DE ROSA / AFP/File
Chief Paris 2024 organizer Tony Estanguet, seen here with mascots, has tried to stay upbeat © Anne-Christine POUJOULAT / AFP