THE HAGUE (Reuters) - Deputy Prime Minister Dominic Raab said on Monday Britain backed an International Criminal Court investigation into alleged war crimes in Ukraine "to the hilt".

       After Russia's invasion of Ukraine on Feb. 24, ICC chief prosecutor Karim Khan said he had opened a formal investigation into possible atrocities on Ukrainian soil since 2014, when Moscow-based separatists seized part of the country's far east.

       "It is important to get the deterrent message out to commanders on the ground in Ukraine and in Moscow that if they commit war crimes they could end up not just in the dock of a court in The Hague but in a prison cell," Raab told journalists in The Hague after meeting Khan.

       He added that for this to be a credible message, Britain and other countries needed to offer the ICC "extra support" to fulfil its mandate in Ukraine. He did not give specifics.

       A British government statement said London was offering police and military analysis and specialist IT help to collect and preserve evidence for the ICC, as well as legal expertise.

       When he announced the investigation, Khan said his office was scrambling for resources and needed everything from investigators to forensic language experts and psycho-social support.

       Raab also declined to say whether the resources to be offered by Britain would be earmarked solely for Ukraine or whether they could also be used for some of the ICC's 16 ongoing investigations and trials.

       He rejected any suggestion that such financial support for a specific investigation could unbalance the court's caseload.

       "There are rules and provisions in place to avoid any perception of bias. The court is totally independent," he said.

       (Reporting by Stephanie van den Berg; Editing by Mark Heinrich)