"Their number will gradually decrease, they will be shot down... But of course, these deliveries will not have any significant impact on the development of events on the front," Kremlin spokesman Dmitry Peskov said.

For more than two years, Ukraine has pleaded with Western allies for the US-made fighter jets -- long considered the crown jewel in the sprawling list of military hardware Kyiv has sought from its Western backers.

For decades, the F-16 has been touted for its precision, speed and range.

Kyiv hopes the arrival of the fighters will enable it to better protect itself from Russian bombardment.

Several NATO countries have pledged to supply varying numbers of the fighter jets and have been training Ukrainian pilots and crews for months.

Amid a blistering Russian air campaign in recent months, President Volodymyr Zelensky has placed Ukraine's need for improved air defences at the top of his agenda at meetings with allies.

During an interview with AFP in May, Zelensky said Ukraine needed around 130 F-16s to secure parity with Russian aviation.

Ukraine's partners, however, have promised less than 100 F-16s to date, with most of the planes likely to arrive over the course of years following the substantial training of the pilots that will fly them.