Police tighten security after foiled bomb attack on Bank of America office in Paris

PARIS - France has increased security at sensitive sites across Paris after a foiled bomb attack on Bank of America's BAC.N offices that prompted some other U.S. banks in France and Germany to allow their staff to work remotely on Thursday.

Citing an elevated "terrorist threat", Paris police said they had reinforced protection around religious and cultural sites, diplomatic premises and some economic venues, as well as across the wider metropolitan region.

Four suspects, including three teenagers and an adult, have been placed under formal investigation for their alleged role in last week's attempted attack, French anti-terrorism prosecutors said on Wednesday.

The adult is suspected of recruiting the teens and paying them between 500 and 1,000 euros ($580-$1,160) to plant and film themselves placing the bomb. All four, who are in pre-trial detention, deny terrorist intent.

Their improvised explosive device, a five-litre petrol can taped to a large pyrotechnic charge, was the most powerful of its kind identified in France to date, prosecutors said.

FRENCH POLICE SUSPECT PRO-IRANIAN GROUP

The police have said they suspect the foiled plot is linked to HAYI, a pro-Iranian group that had posted a video naming Bank of America's Paris headquarters. However, prosecutors say the link is yet to be confirmed.

Goldman Sachs told its Paris staff they could work remotely on Thursday, a source familiar with the matter said, while Citigroup C.N staff in Paris and Frankfurt are also working remotely. It is a precautionary measure, Citi said in an emailed statement to Reuters.

French President Emmanuel Macron commended authorities for thwarting the scheme.

"I want to stress that we are highly vigilant on all these matters, and also to reassure those who may be targeted, in France and elsewhere, as several other European countries have faced similar types of attempted attacks," he said while on a trip in South Korea.

Officials are concerned theconflict with Iran, which began with U.S. and Israeli attacks at the end of February, could inspire attacks in France. The national psyche has been scarred by Islamist militant attacks in 2015 that killed 130 people in November and 17 in January, prompting tougher security laws.

-Reporting by Mathieu Rosemain, Dominique Vidalon, Anousha Sakoui. Editing by Inti Landauro, Jane Merriman, Gabriel Stargardter and Barbara Lewis/Reuters