US entertainer Ariana Grande has suspended her Dangerous Woman tour following the attack on her Manchester show which killed 22 people.
A spokesman for the 23-year-old announced the decision on Wednesday evening following widespread speculation that dates would be affected.
"Due to the tragic events in Manchester the Dangerous Woman tour with Ariana Grande has been suspended until we can further assess the situation and pay our proper respects to those lost," a statement said.
"The London O2 shows this week have been cancelled as well as all shows through June 5 in Switzerland.
"We ask at this time that we all continue to support the city of Manchester and all those families affected by this cowardice and senseless act of violence.
"Our way of life has once again been threatened but we will overcome this together. Thank you."
Grande is scheduled to perform six dates in Australia and New Zealand in September.
Police have arrested six more suspects in Libya and Britain, including the father and brother of the man believed to have carried a bomb into Manchester Arena, as the attack was linked to a terrorist network.
Libyan authorities said special forces had arrested the brother of Salman Abedi, the suspected Manchester attacker, on Tuesday.
Hashem Abedi, the alleged attacker's brother, confessed that he and Salman Abedi were both members of the Islamic State extremist movement, according to a statement by Libyan special forces on Facebook.
Hashem Abedi also said he had visited Britain to help prepare the Manchester attack and he was "clearly aware of the details of this terrorist operation," the statement said.
He had been under surveillance since he left Britain in mid-April and had remained in constant contact with Salman Abedi, it said.
Ramadan Abedi, the father of Salman, was arrested near his home in Tripoli, Libyan authorities said.
In Britain, police arrested four more suspects linked to Salman Abedi, who killed 22 people at Manchester Arena at the end of a concert by US singer Ariana Grande.
Grande has cancelled all upcoming concerts through June 5 following the bombing, a statement from her manager said.
"I think it's very clear that this is a network that we are investigating," Greater Manchester Police Chief Constable Ian Hopkins told reporters when asked whether police are looking for a possible bomb maker.
Hopkins declined to elaborate and gave no details about Wednesday's three arrests in south Manchester and one in the town of Wigan, 25 kilometres from Manchester.
Watch: Manchester police arrest suspect in Wigan
The Wigan suspect was carrying a package which the police were investigating, police said, without giving further details. The most recent arrest was a woman at a Manchester block of flats.
Police announced the arrest of the first suspect, a 23-year-old man rumoured to be the older brother of the attacker, on Tuesday.
The Times, citing CCTV footage recovered by police, said Salman Abedi had placed a suitcase in the foyer of the concert hall shortly before the explosion.
The newspaper quoted a friend as saying Abedi, who died in the explosion, had returned to Britain from Libya just days before the attack.
British and French officials said earlier Wednesday that Abedi probably had accomplices and had links to Islamic State.
French Interior Minister Gerard Collomb told French broadcaster BFMTV that British officials had said Abedi had been "radicalised" and had probably travelled to Syria during a trip to Libya.
Collomb said Abedi's links with the Islamic State group were "proven."
May raises UK threat level to 'critical'
The British government has not confirmed those details about Abedi, whose parents are from Libya, but Home Secretary Amber Rudd told Sky News that he had been known to security services "up to a point" before Monday's attack.
In a separate interview with BBC Radio 4, Rudd said it appears likely that Abedi was not acting alone.
Poland's Foreign Ministry confirmed on Wednesday that at least two Polish citizens died and one was among the 59 injured in the attack in the northern English city.
Many of Monday's victims, who included an eight-year-old girl, have yet to be named, with desperate relatives still appealing for help in finding those missing.
Hopkins confirmed on Wednesday that an off-duty policewoman was among those who died.
Prime Minister Theresa May raised Britain's terrorism threat level to the highest level of "critical" late Tuesday, meaning a further attack is likely or "imminent."
Armed police will increase patrols and military personnel will be deployed at events such as concerts and sports matches.
US leaks 'irritating'
Britain also has a national election scheduled for June 8.
All campaigning was suspended after the attack, although major parties said they would resume some activities on Thursday and national-level campaigning on Friday.
The government said a minute's silence would be held at all official buildings at 1000 GMT (6.00 a.m. ET) on Thursday.
Greater Manchester Police said they were now confident they knew the identity of all the people who lost their lives and had made contact with all the families. They said they would formally name the victims after forensic post-mortems, which would take four or five days.
The bombing also left 64 people wounded, of whom 20 were receiving critical care for highly traumatic injuries to major organs and to limbs, a health official said.
Interior minister Amber Rudd said the bomber had recently returned from Libya. Her French counterpart Gerard Collomb said he had links with Islamic State and had probably visited Syria as well.
Rudd also scolded US officials for leaking details about the investigation into the Manchester attack before British authorities were ready to go public. The New York Times later published detailed photographs of the suspected remnants of the bomb.
Rudd was asked by the BBC about the fact that information about Abedi, including his name, had come out of the United States before it was cleared by British authorities.
"The British police have been very clear that they want to control the flow of information in order to protect operational integrity, the element of surprise, so it is irritating if it gets released from other sources, and I have been very clear with our friends that should not happen again."
France, which has repeatedly been hit by devastating militant attacks since 2015, extended emergency powers.
