Russia-Ukraine war: Explosions heard in Russia's Saratov as air raid sirens sound

What's happening in Saratov?

Explosions have been heard in the Russian city of Saratov, witnesses said early on Monday, as air raid sirens sounded across the city. Social media footage showed orange flashes lighting up the night sky.

The explosions come as Russia continues to target Ukrainian cities with missiles and drones, and as Moscow accuses Kyiv of preparing to use a "dirty bomb" - an explosive device laced with radioactive material.

What has Russia said about the explosions?

Russia's defence ministry said that one of its military facilities in the Saratov region had been attacked by a Ukrainian drone, which was shot down.

The ministry said that three servicemen were killed in the attack, and that no damage was caused to civilian infrastructure.

What has Ukraine said about the explosions?

Ukraine has not yet commented on the explosions in Saratov. However, Kyiv has previously denied Moscow's accusations that it is preparing to use a dirty bomb.

Ukrainian President Volodymyr Zelensky has said that Russia's claims are "a lie" and that Moscow is planning to use a dirty bomb itself.

What is the situation in Saratov?

Saratov is a city of around 800,000 people located in southern Russia, about 800km (500 miles) southeast of Moscow.

The city is home to a number of military facilities, including an air base and a missile factory.

What is the latest on the Russia-Ukraine war?

The war in Ukraine continues to rage, with no end in sight. Russia has been targeting Ukrainian cities with missiles and drones, while Ukraine has been mounting a counteroffensive in the east of the country.

The fighting has caused a humanitarian crisis, with millions of people displaced and thousands killed.