Hello. The damage caused by a container ship that crashed into the Francis Scott Key Bridge became clearer as dawn broke over Baltimore. BBC reporters on the ground are following the latest developments. In Russia, President Vladimir Putin acknowledged involvement of "radical Islamists" in the Moscow concert hall attack. Frank Gardner explains who the jihadist group blamed for the massacre is. Finally, disinformation researchers find signs of a co-ordinated social media campaign that amplified divisive content about the Princess of Wales.

QUESTIONS ANSWERED

The jihadists behind the Moscow attack

IS released a video showing the four attackers with their faces blurred. 

A jihadist group known as Islamic State-Khorasan (IS-K) has claimed responsibility for Friday's deadly attack on a concert hall in Moscow, Russia's capital. IS-K is a regional affiliate of the Islamic State group, which has been proscribed as a terror organisation by governments across the world. 

What do we know about IS-K?

Focused on Afghanistan, Iran and Pakistan and into Central Asia, IS-K has been around for nine years. In recent months, it has emerged as the most dangerous branch of the Islamic State group, with a long reach and a reputation for extreme brutality and cruelty. In Afghanistan it is waging an insurgency against the Taliban, who it opposes on ideological grounds.

Why does the group consider Russia an enemy?

Islamic State's hostility to Russia goes back to the Chechen wars in the 1990s and early 2000s, when Moscow's forces devastated the Chechen capital Grozny. More recently, Russia entered the Syrian civil war on the side of its ally, President Bashar al-Assad, killing large numbers of Islamic State group and Al-Qaeda-linked fighters.

Has IS-K previously targeted Russia?

In Russia, the group has carried out numerous small-scale attacks, the most recent being in 2020 - and already this year the FSB, Russia's internal security service, says it has stopped several terror plots. IS-K views Russia as being an ally of the Taliban in Afghanistan, which is why they attacked the Russian embassy in Kabul in 2022, killing at least six people and injuring others. 

• Kremlin's reaction: Russian President Vladimir Putin has now blamed "Islamists" for the attack, but he still claimed that they had some link to Kyiv and the West - an allegation Ukraine has rejected as absurd. 

• False claims debunked: Through Russian officials' statements, media reports and social media posts, BBC Verify examines how the campaign to blame Kyiv unfolded.

THE BIG PICTURE

The Russian factor driving royal rumours

The Princess of Wales was the subject of rumours and conspiracy theories on social media. Credit: PA Media

Researchers at Cardiff University found a Russian disinformation group was involved in systematic attempts to further intensify the wave of rumours about the Princess of Wales, with royal hashtags being shared billions of times across a range of social media platforms.

And finally... in South Korea

Traffic in the city of Seongnam came to a halt on Tuesday morning as an escaped ostrich ran down the streets. The graceful bird managed to dodge most vehicles, and sprang back up even after being hit by a truck. It's now been returned to the nearby ecological park from where it escaped.