The use of Snatch Land Rovers by British forces in Iraq is to be reviewed, the defence secretary says.
Roadside bombs have increased concern about the Land Rovers
Des Browne told MPs he could not fail to be aware of concerns about the vehicles after recently visiting Iraq.
The vehicles have been criticised for being a "soft target", especially for the roadside bombs that have killed a number of UK soldiers.
Tory shadow defence secretary Liam Fox says UK troops should receive the same protection as their US colleagues.
The Land Rovers are designed to withstand small arms fire but are vulnerable to roadside bombs or rocket-propelled grenades, said the BBC's world affairs editor John Simpson.
Mr Browne's comments in the Commons follow angry criticism from the father of one of the troops in Iraq killed while travelling in the Land Rovers.
Roger Bacon's son Matthew was an army intelligence officer who was killed when a roadside bomb exploded close to his Land Rover last September.
He told the BBC: "We became extremely angry that our troops are out there virtually unprotected, and we just feel that something should have been done before - if they were going to be in that situation, then they should have properly armoured equipment."
Our correspondent says 18 British troops have been killed by roadside bombs while travelling in Land Rovers.
It equates to almost a quarter of British soldiers killed in hostile action, Conservative MP Roger Gale told the Commons.
"These vehicles are widely recognised to be inadequately armoured to withstand roadside bombs and in consequence are seen as a soft target for insurgents," he said.
Mr Gale asked what vehicles Mr Browne was considering using to replace them.
The defence secretary said the Snatch Land Rovers had been "a good and popular option earlier in the campaign" as they were mobile, a good all rounder and the "right profile" to help British troops work with local Iraqis.
"Thundering down narrow streets with battle tanks was not exactly the particular vision that we wanted to give the people of Basra and other parts of south east Iraq of our troops," said Mr Browne.
But he acknowledged there had been a surge of violence in Basra and there had been a radical change in the type of weapons used.
"This is a serious issue. I've asked for a review into this," he said.
"There are medium and long-term plans in relation to vehicles and I will be looking in the short-term at what we can do to respond to the situation."
Dr Fox added that Snatch Land Rovers did not offer "the level of protection our troops need in Iraq - yet we continue to use them.
"Our troops are quite right to demand the level of protection afforded to their American colleagues. They must be asking if the MoD is acting through complacency or incompetence."
UK ARMY SNATCH LAND ROVER AND THE RG-31 ALTERNATIVE
Name: Snatch Land Rover
Defences: Armour to protect against explosions and ballistics; roadside bomb detectors
Strengths: Quick land transport for up to six troops
Weaknesses: Questions over level of protection offered
Cost: Approximately £50,000
Name: RG-31 - made by OMC
Defences: All-steel armoured hull protects against mines and small arms fire
Strengths: V-shaped underside pushes blast outwards
Weaknesses: Questions over mobility and maintenance