Updated

LONDON (AP) — Britain's defense secretary said Friday that senior military posts could be axed as he prepares major spending cuts and a sweeping overhaul of the country's armed forces.

Liam Fox, who visited Afghanistan this week to talk with troops, must decide within weeks how to slash his department's budget, as the country's coalition government seeks to quickly reduce record national debts.

"The prime purpose of what we are doing is to make sure that our armed forces on the front line have everything they need, and all the support they require, to carry out their mission successfully and safely," Fox said, making a speech in London. "That means that the back room sometimes has to do without to make sure that the front line gets what it wants."

Fox indicated there are likely to be job losses among both military and civilian staff as the defense ministry undergoes a "cultural shift which will see a leaner and less centralized organization."

Analysts predict about 30,000 of Britain's 175,000 armed forces personnel are likely to be cut — probably 20,000 from the army, and about 5,000 each from the air force and navy.

Attending a parade at the Royal Military Academy, Prime Minister David Cameron told troops and dignitaries the pending cuts would be challenging.

"There will be difficult decisions ahead, but I will never forget that defense of the realm is the first duty of any government," Cameron said at the academy, in Sandhurst, western England. Yemen's President Ali Abdullah Saleh and Afghanistan's deputy interior minister Munir Mangal also watched the ceremony.

Fox said a review due to be completed by October would likely recommend radical reforms to both military and administrative structures. "This needs to be the defense review that puts the Cold War to bed. This needs to be the defense review that changes the way Britain looks at the world around it," he said.

He confirmed that ministers will consider trimming the number of personnel in senior ranks under the cost-saving measures. "We cannot demand efficiency from the lower ranks while exempting those at the top," he said.

Britain's military is carrying out the first major review of its capabilities and priorities since 1998, and attempting to find savings of up to 9 billion ($14 billion) to its annual budget of about 36 billion pounds ($56 billion).

Fox acknowledged that tricky negotiations are continuing with Britain's Treasury over who will pay for a 20 billion pounds ($32 billion) upgrade to the country's nuclear weapons system.

Treasury chief George Osborne has said the defense ministry would likely need to pay for the program entirely from its own budget. Previously, the central government has paid a share of the costs, as a nuclear deterrent has been seen a key national asset.

"How that budget is funded to take account of that is a conversation that is constantly ongoing with the Treasury," Fox said.