[Whitfield:] All right. We're following a developing story out of France where people say four female American tourists were attacked with acid. It happened earlier today at a train station in Marseille. Police say, two of the victims were taken to the hospital, they say the attacker was a mentally unstable woman. She was arrested and later hospitalized, there is no evidence that the attack was terror group-related. London police have arrested a 21-year-old man, the second arrest in connection with Friday's train explosion. Police have also searched a house in a suburb west of London. An 18-year-old man police arrested Saturday remains in custody. The terror threat level has now been downgraded to severe, meaning a new attack is still considered highly likely. Thirty people were injured when a bomb a partially detonated in a train during rush hour Friday morning. British Prime Minister Theresa May is headed to the United Nations this week and says the terror threat will be at the top of her agenda.
[Theresa May, British Prime Minister:] One of the issues we really need to be addressing and I'll be raising this when I'm at the United Nations is, the question of the use of the internet by terrorists for terrorist planning, but also this use for using it for the spread of the extremism of hatred, of propaganda that can insight and can inspire terrorism.
[Whitfield:] CNN's Nick Paton Walsh is following the story for us from London. So how much do we know about the latest arrest?
[Nick Paton Walsh, Cnn Senior International Correspondent:] Minimal about this 21-year-old arrested in Hounslow, that's out of the west of London. That occur just 10 minutes before midnight just in the past day, just now. Now that resulted in house being searched also in the
[Whitfield:] And the prime minister had said that Donald Trump's sentiments about the Friday attack was not helpful. She said such speculation was not helpful. How is that relationship being measured between she and the president of the United States?
[Walsh:] All right. Theresa May is always has been I think keen to show that she can be chummy with Donald Trump. Oddly enough they hail from sort of similar parts of political spectrum of elements of Theresa May's party here, but [inaudible] nationalistic and protectionist as we see in the United States as well. But even Theresa May's own home secretary, her leading law enforcement official here Amber Rudd today said when questioned about whether or not Donald Trump's suggestion that the police had the attackers, persons been in their sights while it occurred. She said that was quote, pure speculation, and said that she wouldn't be the first person, I'm paraphrasing here, the first person to encouraged Donald Trump not to be tweeting on his phone. So, a definitely a fought relationship here the issue of whether Donald Trump will come visit London while in this constantly been on the discussion here because the board
[Whitfield:] All right, Nick Paton Walsh in London, thanks so much. All right, a mystery in Cuba after a series of suspected sonic attacks leave U.S. diplomats and their family suffering now. The U.S. is considering shutting down the Havana Embassy. We'll bring you the latest, next.