David Schlesinger, the editor-in-chief of Reuters News, told staff in an internal memo that more than half of the 140 journalists job cuts would be in Europe, where there are areas of duplication in coverage since the two companies merged.
Schlesinger wrote: "Unfortunately, the overlap we've found and our need to run the operation efficiently means that we will have to eliminate around 140 jobs worldwide by the end of the year.
"More than half the cuts will occur in Europe, the area of most duplication -- the rest will be scattered. Thomson Financial News will be totally absorbed into Reuters News by end of 2008, and sooner if possible."
He said that Thomson Reuters would add some 50 jobs for new projects in key areas.
A Thomson Reuters spokeswoman confirmed the journalists job cuts, as well as the proposed cuts to the sales and technical teams, which were announced to staff in a separate memo last week.
Around 650 posts in the content, technology and operations division will be axed worldwide and around 45 sales positions in the group's EMEA division will also be cut.
Schlesinger said that consultation with affected unions, works councils and staff will begin "immediately".
Thomson agreed last May to acquire Reuters, with a cash-and-stock offer that valued the 157-year-old news agency at £8.7bn. The merged group employs around 50,000 staff in 93 countries.