Smoke billows from inside the Pakistani naval base after the attack late on Sunday. [EPA]


 At least four people are reported to have been killed in an ongoing attack by armed men on a military base in the Pakistani city of Karachi.
Some of the attackers are still inside the base and commandos and marines are continuing to battle them five hours after the assault began, Al Jazeera's Kamal Hyder said.
According to our correspondent, at least a dozen men attacked the Mehran base, a key naval aviation facility, late on Sunday. Two martime patrol aircraft were destroyed and at least nine people were also wounded in the assault.
He said "the attack raised a lot of questions as to how such a large number of people, so well armed, could have actually gotten into the base"..

'Terrorist attack'
The local government said that the base was under "terrorist attack".
Aamir Latif, the bureau chief of Pakistan's Online News, told Al Jazeera that a firefight was still under way as security forces attempted to wrest control of the base.
"Militants have taken control of a building inside the base though it is unconfirmed if they are taking hostages there or not."
Intelligence officials said that between 15 and 20 attackers were inside the base, and had attacked three hangars housing aircraft.
A military spokesman said two Pakistan Navy staff were killed in the attack.
"One of our officers and one Navy personnel have been martyred," Commodore Irfan ul Haq, a spokesman for the Pakistan Navy, told the AFP news agency.
Five explosions were heard at the base ahead of the attack, according to Pakistani Express TV.
Yusuf Raza Gilani, Pakistan's prime minister, condemned the attack.
"Such a cowardly act of terror could not deter the commitment of the government and people of Pakistan to fight terrorism," Gilani said in statement.
No group has claimed responsibility for the attack, but al-Qaeda-linked Taliban fighters have vowed to avenge the killing of Osama bin Laden, the al-Qaeda leader, by US special forces.
They have carried out several attacks since his death on May 2.