Russia fired at least 70 rockets at targets in Ukraine on Saturday, as U.S. President Joe Biden visited neighboring Poland, but only eight of them hit their targets, according to reports.

The Russian independent investigative journalism website The Insider reported that Russia fired 52 missiles from Black Sea Fleet ships based around Sevastopol and at least 18 from inside Belarus.

It was the highest daily number of missiles fired by Russia in the conflict so far, and only eight hit their targets as many were shot down, the website reported.

Some of the missiles fell on Lviv and other Ukrainian areas close to the Polish border, in a move possibly designed to provoke NATO members.

Despite it being more than a month into the war, security has been surprised that Russia hasn’t managed to gain control of Ukraine’s airspace. Ukraine’s staunch defense of it has managed to halt the progression of the Russian military, dragging the war into a stalemate and prompting Russia to change its strategy.

In its most recent update on the conflict, Ukraine’s ministry of foreign affairs tweeted on Sunday that some 16,600 Russian military personnel had been killed, while its air force has suffered heavy losses, with 121 aircraft and 127 helicopters either destroyed or captured by Ukrainian forces or abandoned by the Russians. Fifty-two Russian anti-aircraft warfare systems had also been lost. Russia hasn’t released a recent update on numbers in this regard.

There have also been reports and social media posts about a fighter pilot dubbed the “Ghost of Kyiv,” who is said to have single-handedly brought down six Russian planes since Vladimir Putin launched the invasion of Ukraine on February 24. The reports are unverified.

On Monday, U.S. officials and military analysts told the Washington Post that the air war over Ukraine appeared to have entered a new phase, with Russia’s air force boosting the number of daily flights by 50 percent and deploying an increasing number of Russian drones and munitions over the battlefield.