A government-backed Qatari firm laid out plans on Monday to invest $250 million (£153m) in a Barclays PLC natural resource investment business.
The Qatar Asset Management Co (QAMC) said it will invest the funds into current and future holdings of a private equity business run by the British bank.
A "substantial proportion" of its investment is destined for the $2.1 billion (£1.3bn) worth of assets already held by the business, known as Barclays Natural Resource Investments (BNRI).
BNRI invests in companies involved in oil and gas, mining and other resource industries on behalf of investors around the world.
QAMC is run by the Qatar Financial Centre Authority, which oversees the Gulf state's financial sector, and the country's Qatar Investment Authority sovereign wealth fund.
Already the world's largest supplier of liquefied natural gas, Qatar has recently been pumping money into mining company Xstrata PLC.
Documents revealed on Monday state-run Qatar Holding owned more than 7 per cent of the Anglo-Swiss company, which is being taken over by commodities trader Glencore International PLC.
Qatar Holding is the main investment arm of the QIA sovereign wealth fund. It has also been building stakes in European energy companies such as French oil giant Total SA and gold miner European Goldfields.
Qatar Holding is also one of the biggest direct investors in Barclays, with a 6.7 per cent stake.
As part of deal, BNRI plans to open an office in the Qatar Financial Centre, a banking hub in a new part of the Qatari capital Doha that has struggled to attract big financial companies to set up shop. Barclays already has operations there.
Defence Secretary Philip Hammond believes himself vindicated by the High Court ruling that his Iraq Historic Allegations Team (IHAT) is independent.
A look at the causes and possible outcomes of Silvio Berlusconi and his right-wing coalition's lead in the polls.
Attacks such as yesterday's horrific murder in Woolwich didn't happen before the 'war on terror.' It's time we recognised the consequences of the conflicts we've unleashed