At least 30 people have been killed and 46 wounded in four suicide bombings in the southern Afghan city of Kandahar, hospital officials say.
The first blast happened at about 2000 (1530 GMT). Officials said the biggest attack was aimed at the city's main prison.
The Taliban said they carried out the bombings as a "message" to Nato.
The US has hinted that the volatile area could be one of the next targets for operations against the Taliban.
The BBC's Quentin Sommerville, in Kabul, says Kandahar, one of Afghanistan's largest cities, is the Taliban's "spiritual home".
President Hamid Karzai's half-brother, Ahmad Wali Karzai, who is the head of Kandahar's provincial council, told the BBC the first suicide attack involved a vehicle targeting Kandahar's main prison.
MAJOR KANDAHAR ATTACKS
17 Feb 2008: 100 killed by suicide bomber at a dog fight
25 Aug 2009: Car bomb in shopping area kills 43
13 June 2008: 900 inmates flee after truck bomb blasts hole in jail
18 Feb 2008: Blast targeting Canadian troops kills 37 civilians
5 Sept 2002: Bombing in city centre kills at least 30, followed by attempt on President Karzai's life
13 Mar 2010: At least 27 killed in four suicide attacks across city
The second explosion came from a motorbike parked near his home, he said, while another involved a suicide bomber on a bicycle who targeted a police vehicle.
The fourth blast was at Kandahar police headquarters, where four policeman were confirmed dead.
A wedding celebration was taking place nearby and a number of guests were believed to be among the dead and injured.
In June 2008, a suicide bomber blew apart the Kandahar prison gates and a nearby checkpoint, freeing hundreds of prisoners, many of them suspected insurgents.
But Ahmed Wali Karzai said this time, the walls of the prison were not breached, but that nearby buildings were badly damaged.
The head of the city's main hospital, Abdul Qayyum Pukhla, was quoted as saying that both civilians and police were among the dead in the attacks.
Western troops were assisting at the request of Afghan authorities, said Major Macen Waoczak, a spokesman for the Nato-led International Security Assistance Force.
Earlier on Saturday a roadside bomb killed six people travelling in a civilian vehicle in the capital of Uruzgan province in central Afghanistan.
The blasts came as Nato and Afghan forces continued a major operation against Taliban militants in neighbouring Helmand province.
The top US commander in Afghanistan, General Stanley McChrystal, has hinted in recent weeks that the Kandahar area could be one of the next targets for operations against the Taliban.