Leaders of Poland and Ukraine sign security accord in Warsaw

Ukrainian President Volodymyr Zelensky and Polish Prime Minister Donald Tusk signed a bilateral security agreement in Warsaw on Monday, a day before the start of a NATO summit in Washington.

"Those who defend Ukraine today are also defending themselves," said Tusk.

Zelensky called the agreement "ambitious."

"It is capable of protecting the lives of our people and resisting Russian evil," said Zelensky.

The treaty provides for the development of a plan by which "Russian missiles and drones fired in the direction of Poland can be shot down in Ukrainian airspace," according to the Ukrainian president.

The agreement also states that Poland is examining the possibility of delivering further MiG-29 fighter jets to Ukraine. Poland has already delivered 10 such fighter jets to Kiev.

According to Ukrainian media, 14 more jets are now being considered. However, Tusk emphasized that the prerequisite is that Poland receives adequate replacements.

The Polish government will also encourage Ukrainian citizens living in the country to join the Ukrainian military. Zelensky said that a unit of Ukrainian volunteers should be formed and trained in Poland, which would then fight in Ukraine.

In the early afternoon, the Ukrainian leader met his Polish counterpart Andrzej Duda.

Zelensky arrived in Poland as his nation was battered by waves of powerful Russian missile attacks, with at least 26 people killed and a large children's hospital hit in Kiev.

"There are no words, no documents, no political statements that would suffice to condemn the aggressor," said Tusk.

Poland is one of the most committed political and military supporters of Ukraine as Kiev seeks to fend off the full-scale invasion, now in its third year.

Poland is also an important hub for Western military aid to Kiev.

Plus, it has taken in almost 1 million Ukrainian refugees fleeing violence in their country.

Ukraine has already made security agreements with the EU and 19 individual states, including the United States, Japan and Germany, to formalize the military and civilian support that has been provided already and hold out the prospect of further aid for an initial period of 10 years.