WASHINGTON - The US State Department has approved a sale of Javelin missile systems worth about 780 million US dollars to Poland, days after an alleged Russian drone incursion into Poland's airspace alerting NATO members, the US Defense Security Cooperation Agency (DSCA) said in a statement issued on Thursday.

The agency said it has notified Congress of the proposed sale, which includes 2,506 FGM-148F Javelin missiles and 253 lightweight command launch units.

The package also covers training, simulation rounds, spares, tool kits, battery coolant units, transportation and technical assistance from both the US government and contractors, according to the statement.

The DSCA said the sale aims to enhance Poland's ability to meet NATO requirements and defend its territory by upgrading older command launch systems and expanding its missile inventory.

According to principal contractors, Javelin weapons systems is the world's premier shoulder-fired anti-armor system. With its soft launch design, Javelin can be safely fired from inside buildings or bunkers.

The Polish military shot down drones that "repeatedly violated" Poland's airspace last week. In response, US President Donald Trump said that the alleged Russian drone incursion "could have been a mistake".

"We would also wish that the drone attack on Poland was a mistake. But it wasn't. And we know it," Polish Prime Minister Donald Tusk said on social media, dismissing Trump's suggestion.

Russia has rejected the accusation made by Poland, the EU and NATO that it launched the drones. A number of European leaders accused Russia of carrying out a deliberate drone incursion to test the readiness of NATO.