Says meeting with pope was the 'honor of a lifetime.'
More suspects arrested as Britain raises terror threat level.
22 people were killed by a suicide bomber at a concert Monday night.
Chinese finance ministry criticized the decision.
Organization Trump once declared obsolete opening a massive new headquarters.
Said to be the first time the extremist group has claimed attack in region.
Survivors recount horror of suicide bombing at concert.
President Trump, Pope Francis set to meet for first time Wednesday.
Security at major events a concern even before Monday's suicide bombing in UK
Party draws mobs of celebrities and a dozen former Palme d'Or winners.