Criminal charges could be brought against traders implicated in the interest rate rigging scandal after the Serious Fraud Office announced on Friday that it had begun a formal investigation into attempts to fix Libor.

The director of the SFO David Green said he had "decided to formally accept the Libor matter for investigation" after reviewing the information provided by regulators which last week fined Barclays £290m for attempting to manipulate the price of the key interest rate known as Libor - the London interbank offered rate.

The investigation is understood to be into the wider market and not just Barclays.

Romanian politicians impeached President Traian Băsescu in an overwhelming vote on Friday, paving the way for a national referendum that could see the divisive and increasingly unpopular leader ousted from the position he's held for eight years.

The vote of 256-114 in parliament came as Băsescu and Prime Minister Victor Ponta have engaged in a bitter power struggle in the eastern European country of 19 million, which emerged from communism in 1989. The machinations, especially attempts to sideline the judiciary, have led the United States and the European Union to issue statements of concern about Romania's democracy.

Băsescu opponents accused him of overstepping his authority by meddling with the prime minister's office and trying to influence judicial affairs. The 60-year-old former ship captain was also accused of making racist remarks about Gypsies and disabled people.

Senate speaker Crin Antonescu, who will serve as interim president now that Băsescu has been effectively suspended from the role, said a popular referendum on Băsescu's fate will be held on 29 July.

Spain's borrowing costs soared back to crisis levels on Friday after infighting among eurozone countries signalled a return to the turmoil that has rocked the global economy in recent months.

The interest rate on Spanish bonds touched 7%, leaving Madrid on the brink of asking Brussels for a formal bailout, despite having secured a €100bn rescue facility for the country's banks.

Stock markets plunged and the euro tumbled as investors withdrew funds from the currency zone in favour of safer havens. The euro fell 1% to its lowest level against the dollar since July 2010. Spain's Ibex index of leading shares was down more than 3%. The German Dax fell almost 2% to 6410 and the French CAC 1.9% lower at 3168. The FTSE dropped 30 points to 5662, while the New York Dow Jones index fell 138 points to 12,719.

A report on the jobs market in the US added to market tensions after it appeared to show the powerhouse of global growth hitting the buffers. The US added only 80,000 jobs last month, well short of the 200,000 average it managed until March and the 400,000 it needs to bring down unemployment.