Taliban suicide bombers struck across Afghanistan's southern city of Kandahar on Saturday, killing 30 people and wounding scores in a series of strikes the militants called a message to NATO.

The city is at the center of the Taliban's heartland and the next major target for NATO forces this year.

Officials said the biggest attack was aimed at the prison on the city's outskirts, apparently an attempt to repeat a jailbreak there two years ago.

Abdul Qayyum Pukhla, head of Kandahar's main hospital, said 27 dead and 52 wounded had been brought there, including police and civilians.

Provincial council chief Ahmad Wali Karzai, half-brother of President Hamid Karzai, told Reuters 30 people had been killed, many of them women and children at a wedding hall near one of the targets, the police chief's compound.

Two other attacks included a bomb in a motorcycle parked near his own home, and a suicide attack by a bomber on a bicycle, he said, adding he believed the other attacks were intended as diversions from the main strike on the prison.

A Reuters witness said police opened fire at the scene of the blast near the police chief's compound. Windows in nearby buildings were shattered.

In a statement on their website, the Taliban said they had carried out the bombings in the city as a message to NATO commanders planning a large operation there. They said they had inflicted heavy casualties on the enemies of the mujahideen.

PRISON IS MAIN TARGET

The main target was the prison. The prison is very well guarded, Ahmad Wali Karzai told Reuters. It was a very big explosion. It was a huge explosion.

The city is quiet now. Everything is quiet now and under control, he said about two hours after the attacks.

The attack at the prison appeared to be an attempt to repeat a spectacular jailbreak of 2008, when a truck bomber blasted a hole in its mud walls and insurgents freed around 1,000 prisoners, including 400 Taliban fighters.

Ahmad Wali Karzai said Saturday's attempt to free prisoners had failed because fortifications had been built at the prison by Canadian forces since the earlier attack.

A spokesman for the NATO-led International Security Assistance Force confirmed there had been at least three explosions in the city and said foreign troops were assisting at the request of Afghan authorities. He had no further details.

Kandahar, Afghanistan's second city, has been the scene of numerous Taliban attacks. U.S.-led forces plan to launch an operation this year to take back the city and surrounding areas, which have increasingly been under the insurgents' control.

Kandahar was the spiritual homeland of the Taliban when the strict Islamists ruled Afghanistan in the 1990s, and the U.S. and NATO commander, General Stanley McChrystal, considers it the main geographical target of the Taliban leadership.

It is also the home town of the Karzai family.

The bulk of 30,000 additional combat forces ordered to Afghanistan by U.S. President Barack Obama at the end of last year are expected to be deployed in Kandahar as part of the major operation over the next few months. Thousands of Canadian troops also patrol the city.

(Additional reporting by Peter Graff, Hamid Shalizi and Jonathon Burch in Kabul; Writing by Jonathon Burch and Peter Graff; Editing by Myra MacDonald)