Authorities are investigating how a suicide bomber killed at least 100 people at a mosque in a high security zone in Peshawar, Pakistan.
The attack, one of the country's deadliest in recent years, has shocked Pakistanis. Most of the dead were security force members at prayer.
City police who are on the frontline against militants believe they were targeted to demoralise them.
It comes two months after the Pakistani Taliban abandoned a ceasefire.
Since then violence has been on the rise, with frequent attacks on police and soldiers.
A claim that the hard-line Islamist militant group Tehrik-i-Taliban Pakistan (TTP), as it is known, carried out Monday's bombing was later denied by the group, which blamed it on the commander of a breakaway faction.
Some observers are questioning the denial - they suggest it could be a distraction ploy.
In the past the TTP has refrained from claiming some attacks on mosques, schools or markets, preferring to cast its violence as a war with security forces and not against the Pakistani people.
The head of the UN World Health Organization (WHO) said on Wednesday that the agency was working to help contain Marburg virus disease outbreaks in Equatorial Guinea and Tanzania, advocating for more global action to implement a UN-led “One Health” approach.