LONDON (Reuters) - Donor countries pledged $8.9 billion to the African Development Bank to be made available in loans to the continent's poorest countries, the bank said on Monday, a more than 50 percent increase.

Representatives at a donor meeting in London said the focus would be on infrastructure, governance and regional integration promoting agriculture, gender equality, environmental sustainability, climate change adaptation and private sector development, a statement said.

"If we are serious about giving Africa a chance, then we have to be serious about backing African institutions," said British development minister Shirti Vadera. "If not now, when?

The bank said the new pledges increased resources available to its African Development Fund, which provides loans for development projects and is replenished every three years, by 52 percent over the previous 2005 to 2007 period.

The bank said 7.5 percent of the resources would be put into a fund for fragile states recovering from conflict, 17.5 per cent on multinational operations promoting greater integration on the continent and 75 percent distributed based on the performance of African countries themselves, with the aim of promoting good governance and accountability in each country.