Pakistan, July 21 -- Ukraine fired more than 400 drones toward Moscow in its latest major attack on the Russian capital, the city's mayor said Monday.

The blitz came hours after Russia bombarded Kyiv and other Ukrainian cities with ballistic missiles in a relentless cycle of tit-for-tat strikes that make a settlement to end Moscow's more than 4-year-old all-out invasion appear a distant possibility.

Ukrainian President Volodymyr Zelenskyy, meanwhile, said he would hold "key talks" on Monday as he tries to defuse a domestic political crisis after last week's government reshuffle exposed a deep split between the military's old guard and young innovators over how to fight the war.

Zelenskyy needs to reassure Ukrainians that sacrificing 35...