President Volodymyr Zelenskyy on Monday urged the North Atlantic Treaty Organization, or NATO, to declare a no-fly zone over Ukraine, Agence-France Presse reported.

A no-fly zone bans planes from flying over a defined area. These areas are used in conflicts to protect civilians by preventing other countries from flying inside their national airspace.

Zelensky made the appeal after Russian troops launched airstrikes in Ukraine’s western city of Lviv, killing 35 people and injuring more than 130 people. The military training ground in Lviv is located near the border with NATO member Poland.

The president added that he had warned NATO last year that Russia would go to war “if there were no harsh preventive sanctions against the Russian Federation”, Agence France-Presse reported. “We were right,” he said. “It is only a matter of time before Russian missiles fall on your territory, on NATO territory, on the homes of NATO citizens.”

On March 5, a poll held by Reuters in the United States found that 74% of the respondents wanted a no-fly zone over Ukraine.

However, US President Joe Biden, on March 12, said that a direct confrontation between NATO and Russia would lead to the third world war.

Russia on February 24 had invaded Ukraine. Russian President Vladimir Putin has described the invasion as a “special military operation” aimed at dislodging the “neo-Nazis” ruling Ukraine.

According to the United Nations human rights office, 474 civilians have been killed and 861 injured in Ukraine. On the Russian side, over 498 of its troops have died, according to the country’s military.

Meanwhile, the fourth round of peace talks between Russia and Ukraine will take place on Monday. “Negotiations go non-stop in the format of video conferences,” Zelenskyy said in a tweet. “Working groups are constantly functioning. A large number of issues require constant attention. On Monday, March 14, a negotiating session will be held to sum up the preliminary results.”