Bangladesh police are investigating the murder of an Italian aid worker who was shot on Monday night.
The Islamic State group says it carried on the attack, shooting dead Cesare Tavella, 50, in the capital Dhaka's diplomatic quarter.
Police Commissioner Asaduzzaman Mia said Tavella was jogging when two attackers fired at him from behind.
The US and UK urged citizens to be cautious, saying they had information Western interests could be targeted.
They have also restricted the movements of their diplomats.