Tony Blair's launch of an initiative for British humanitarian intervention in Africa yesterday was overshadowed by his outspoken companion, Bob Geldof, who accused an EU aid official of "talking out of his arse".

Mr Blair had announced that1,500 British soldiers would be committed to a 10,000-strong European force of "rapidly deployable" battle groups.

The force would be established by 2006, with a mission to "hold the fort" in African conflicts before United Nations or African Union peace-keepers can be deployed. Mr Blair also pledged to train 20,000 African troops in logistics and planning, and warned that war was a major factor holding back the continent's development.

Downing Street said the force would be set up alongside the planned European Rapid Reaction Force. The battle-groups would be deployable for up to three months to intervene in battle zones before African troops can take over long-term peace-keeping work.

Geldof overshadowed the announcement. He was responding in characteristic fashion to claims by Poul Nielson, the EU's development and humanitarian aid commissioner, that British-backed debt-relief plans would force future generations to pay for the glory for today's politicians. Geldof, a co-founder of Live Aid, has campaigned for debt relief for years.

The pop star and anti-poverty campaigner is in Ethiopia with the Prime Minister as one of 17 members of the British-sponsored Commission for Africa.

He was incensed to hear comments by Mr Neilson in Brussels, who argued that the International Finance Facility (IFF) scheme smacked of "innovative Enron accounting" in a reference to the accounting malpractices that led to the collapse of the American energy trade giant.

The IFF, which is backed by Gordon Brown, the Chancellor of the Exchequer, would double aid to $100bn (£56bn) a year by issuing bonds in the capital markets using donor countries' long-term funding commitments as collateral. Mr Nielson said: "To impose on our children in the donor countries the burden of actually paying what we now take the glory for doing, that I don't like."

Geldof responded: "He's talking through his arse, quite frankly. He shouldn't have his job if he doesn't want to help. It's rich of the EU aid commissioner. He should look to his own books. They're wholly woeful in what they do," he said. "The debt relief issue is economic sophistry if that's what he's suggesting. I think the IFF is elegant, timely, simple, necessary."

Geldof's positionwas backed by his conference host, Meles Zenawi, the Ethiopian Prime Minister, who supported the IFF, saying he didn't think of it as an "accounting gimmick".

Mr Blair also backed the scheme, calling for those who opposed the IFF to enter into informed debate about its mechanics.