Western officials also say that explosion that sparked international concern over a possible further escalation of conflict, likely caused by Ukrainian interceptor

As Biden and US officials say the projectiles were likely fired by Ukrainian forces, NATO meeting doesn't appear to focus on perceived threat to a member state

US pledges support for investigation after Poland says 'Russian-made' projectile killed 2 near Ukraine's border, raising fears Western alliance could be drawn into war

Border town of Przewodów reported struck, but Moscow claims it had 'nothing to do' with the incident; Zelensky calls for action following 'very significant escalation'

Ukraine president admits 'price of war is high,' after winning back only regional capital captured by Moscow; NATO secretary-general warns against underestimating Putin's army

Experts say use of Iranian weapons in Ukraine war may be a 'warning' to Western powers; arms sales between the two countries remains a global concern

In first address to parliament, Giorgia Meloni distances her government from country's 'undemocratic' history, says Italy a 'reliable' partner in supporting Ukraine, opposing Putin

Nearly half of alliance's members taking part in annual exercises, which come as Putin threatens to use any means to defend Russian territory

After Russian threats to utilize such weapons against Ukraine, US Defense Secretary Lloyd Austin says 'irresponsible and reckless rhetoric is dangerous'

Denmark says investigation 'continuing and going well' despite presence of munitions along seabed; West accuses Russia of sabotaging undersea gas pipes