The bank, which was at the heart of the Libor interest-rate rigging scandal, also said the overall number of job cuts planned for this year had risen to 14,000.
Barclays had originally said that up to 12,000 jobs would be lost worldwide in 2014 out of a total workforce of about 139,000.
The bank said that the 7,000 investment banking jobs would go by 2016.
"This is a bold simplification of Barclays," chief executive Antony Jenkins said in the statement on Thursday.
"We will be a focused international bank, operating only in areas where we have capability, scale and competitive advantage."
Jenkins added that Barclays would become "leaner, stronger, much better balanced and well positioned to deliver lower volatility, higher returns, and growth".
The bank will meanwhile create Barclays Non-Core - a unit grouping "assets which do not fit the strategic objectives" of the group, the statement said.
"Barclays will look to exit or run down these assets over time," it added.
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