Police in Lahore, Pakistan are hunting for a dozen or more heavily-armed gunmen who ambushed a visiting national cricket team outside the entrance to a city stadium Tuesday, shot seven people dead and then fled the scene without being captured.

The ambush happened around 9 a.m. as Sri Lanka's national cricket team was arriving by bus to a match that was scheduled to take place at the Gaddafi Stadium in downtown Lahore.

The players were being escorted by police vehicles that flanked the front, rear and sides of their bus. It was the same route the convoy had taken for the previous two days when the Sri Lankan cricket squad played matches against Pakistan's own national team.

Some of the gunmen arrived to the scene in rickshaws, while others arrived by car, said Lahore police chief Haji Habibur Rehman.

The assailants carried walkie-talkies and backpacks stuffed with food supplies, suggesting they may have been preparing for a lengthy siege. And they were armed with rocket-propelled grenades, pistols, submachine guns, plastic explosives as well as 25 hand grenades.

The attack began at a traffic circle about 300 metres from the entrance to the stadium, with the gunmen hurling at least one grenade and a rocket at the bus from the interior of a white car, while other gunmen attacked from three other positions.

The bus sped through the line of fire as the players ducked and shouted: "Go! Go!"

Driver Mohammad Khalil said he maneuvered the bus into the stadium as it came under siege.

When the bus made it into the stadium, the focus turned to the status of the players.

Cricket team captain Mahela Jayawardene shouted: "Get more ambulances in here! Get more ambulance in here," said Tony Bennet, an Australian cameraman who was covering the match.

By the time the fighting was over in the street -- 15 minutes after the gunmen began exchanging fire with the police officers who had been protecting the vehicles -- six police officers were dead, as well as the driver of one of the vehicles in the convoy.

Twenty-five bullet holes had been blasted into the cricket team's bus, though none of the cricket players were killed. Seven Sri Lankan players, a Pakistani umpire, and a British assistant coach were injured in the attack, though none suffered life-threatening injuries.

A spokesman for the Sri Lankan High Commission said players Thilan Samaraweera and Tharanga Paranavitana were treated in hospital for their injuries, while the rest of the injured parties suffered minor injuries.

Rehman, the police chief, said none of the attackers were killed or captured at the scene.

Still, Rehman said his officers "sacrificed their lives to protect the Sri Lankan team."

Rehman said the attackers may have been Pashtuns, an ethnic group from close to the Afghan border.

Following the attack, Pakistan's Interior Ministry chief Rehman Malik said the country was "in a state of war."

"We will flush out all these terrorists from this country," he said late Tuesday.

The attacks come just three months after the terror attacks in Mumbai, which were allegedly carried out by militants based out of Pakistan.

It is still unclear who is responsible for Tuesday's attack, though it likely that Lashkar-e-Taiba -- the group blamed for the Mumbai attacks -- will fall under suspicion for Tuesday's ambush in Lahore.

"These people were highly trained and highly armed -- the way they were holding their guns, the way they were taking aim and shooting at the police," said Salman Taseer, the governor of Punjab province, adding that they "used the same methods... as the terrorists who attacked Mumbai."

Sri Lankan President Mahinda Rajapakse called the incident a "cowardly terrorist attack" and sent his foreign minister to Pakistan to help the team return home safely.

In London, International Cricket Council President David Morgan said his organization had no role in allowing the Sri Lankan team to travel to Pakistan because both sides had agreed to the match.

Morgan said hopefully cricket teams will be able to go to Pakistan in the future.

"We must not believe that Pakistan is going to remain unsafe for ever and ever and we must hope that it will not remain unsafe for too long," Morgan told reporters Tuesday.

With files from The Associated Press