Legal experts have advised businesses to pay close attention to their due diligence and know your customer (KYC) processes in order to remain compliant with new sanctions being implemented by the EU and US against Russian officials in the wake of the Crimean crisis.

A number of individuals in the country have already been hit with asset freezes and other restrictions after Russia formally annexed the peninsula earlier this month and speculation continues that the current restrictions will not mark the end of the sanctions.

Tom Stocker of law firm Pinsent Masons said recent events have increased the likelihood of further restrictions on individuals and companies from both Russia and Ukraine, so businesses need to be prudent by taking actions such as subscribing to US government and European Commission updates.

"Other prudent steps include carrying out know your customer due diligence to identify the existence of any politically exposed persons who may be associated with a customer or client, putting in place robust sanctions and termination clauses into any new contracts, and seeking payment in advance of delivery," he continued.

Organisations that breach these sanctions could be facing the possibility of "eye-watering" fines, so it is vitally important they take the time to understand exactly who they are doing businesses with and whether they are on one of the sanctions lists.

The expert also warned European firms that it is not just the restrictions put in place by their own governments and the EU that they need to be aware of, as sanctions imposed by the US could still affect them - even if they believe they have no exposure to US law.

He explained: "The way in which the global financial system works means that most banks are caught by US sanctions. Banks, in turn, require their business customers to comply with US sanctions. US sanctions are therefore far reaching in effect."

The US sanctions also go further than European ones, as they target several prominent Russian businessmen, as well as Bank Rossiya - with asset freezes effectively preventing the firm and its customers from doing business with any western bank. The EU's restrictions, on the other hand, remain targeted at politicians and civil servants for the time being.