Eoin Morgan and Alex Hales will miss England's upcoming tour of Bangladesh. In Morgan's absence, Jos Buttler will captain the one-day side.
It was announced in August that England's tour of Bangladesh would go ahead as planned, following a full risk assessment in the wake of a recent terror attack in the nation's capital of Dhaka.
However, Morgan had expressed uncertainty over the prospect of travelling - and both he and Hales informed England's director of cricket, Andrew Strauss, of their unavailability this weekend.
Wicketkeeper-batsman Jos Buttler will take the reins of the one-day side in Morgan's absence, while former England skipper Strauss said he does not expect any other players to pull out.
In an ECB statement on Sunday, Strauss said: "Whilst we understand and respect Eoin and Alex's decision, we are disappointed that they have made themselves unavailable for selection for the Bangladesh tour.
"We have had open and honest conversations with all the players about the security arrangements in Bangladesh and at this stage we are not expecting any other individuals to withdraw from the tour. Final selection for the Bangladesh tour will now take place on Friday.
"As with all England overseas tours, the safety and security of players and staff is of the utmost importance to ECB.
"We will continue to monitor the situation in Bangladesh, take advice and consider the appropriate steps up to and throughout the five weeks we are on tour."
Following the initial confirmation that the tour would go ahead, an ECB statement read: "Safety and security of players and management are always paramount. We've received a thorough risk assessment, had excellent insight into the current situation and been fully briefed on security commitments.
"ECB and PCA [the Professional Cricketers' Association] have the utmost confidence in the advice and support we've been given."
It remains to be seen whether Morgan will regain the limited-overs captaincy following England's trip to Bangladesh, amid suggestions his decision could lead to his place in the team coming under threat.