Image caption The Kandahar base reportedly came under attack for hours

Insurgents have attacked Nato's main military base in southern Afghanistan.

A Nato spokesman said Kandahar airfield had come under rocket and mortar fire, followed by a ground assault. Several Nato personnel were wounded.

Officials said the attackers had tried to get into the base, but were repelled by security forces.

It is the second attack on a major installation in the last few days - on Wednesday militants attacked the US military base at Bagram.

Nato also said that separate attacks in southern Afghanistan earlier on Saturday killed three Nato personnel and a civilian working with the military.

"Kandahar airfield came under indirect fire at approximately eight o'clock (1530 GMT) tonight and shortly afterward a ground attack was under way as well," Nato spokesman Lt Col Todd Vician told Reuters.

Three British cabinet ministers, led by Foreign Secretary William Hague, were due to visit the Kandahar base later but were forced to change their plans at the last minute because of the attack.

Bunker request

Nato said in a statement that no insurgents had managed to penetrate the base perimeter.

It added that "a number" of military and civilian personnel were wounded and were receiving medical treatment, but there were no confirmed fatalities.

Afghan contractors said five rockets struck the base, including one which hit the helicopter base and another which targeted a shopping area.

Lucian Read, a journalist at the site at the time of the attack, said people were told to get to bunkers, and that a loudspeaker announcement had warned of a ground attack.

The base, which sits on the edge of Kandahar city, the provincial capital, houses around 23,000 personnel and regularly comes under attack.

In an assault on Bagram base on Wednesday, an American contractor was killed in fighting that lasted several hours.

A day earlier, a Taliban suicide bomber had attacked a Nato convoy in the capital Kabul, killing 18 people including six Nato soldiers.

The Taliban recently announced a spring offensive against Nato forces and Afghan government troops.

Earlier on Saturday, Afghan police said they had found a cache of hundreds of rockets on the outskirts of Kabul.