Editorial staff at Rupert Murdoch's remaining upscale London newspapers were informed on Thursday of impending budget and staff cuts, which may include some compulsory layoffs.

A company source said that the principal objective of the move was to make a 12 percent across-the-board cut in budgets at both the weekly Sunday Times and the Monday-through-Saturday daily Times of London.

John Witherow, editor of The Sunday Times, and James Harding, editor of The Times, both announced the cuts to their staff at meetings on Thursday.

At the Sunday Times, the budget cuts were expected to result in compulsory layoffs of between 15 and 20 journalists, or about 10 percent of the newspaper's editorial staff, said two sources familiar with the company's plans.

The Sunday Times will also reduce employment of casuals -- non-staff journalists who work regular shifts at the papers -- by around 30 percent, the sources said.

At the daily Times, up to 100 slots will be cut from 700 full-time, part-time and casual editorial positions which currently exist at the newspaper. Unlike the Sunday Times, the daily paper will offer some staffers the opportunity to leave the paper voluntarily.

The company source said there had been some discussion of consolidating back office functions of the two papers but such plans were not going forward. The source said business staff and budgets at the papers were already being trimmed.

That source went on to say that the papers would retain their current section architecture and denied rumors circulating among some staff that pages in some sections will be reduced.

The company source added that no commensurate cuts are expected at Murdoch's remaining tabloid paper, the six-day daily The Sun.

Earlier this year, Murdoch shuttered The Sun's Sunday stablemate, the News of the World, following uproar over revelations about how its journalists had hacked into voice mails of celebrities, politicians and crime victims.

The Times historically is reputed to have lost millions of pounds sterling for its owners. But the Sunday Times until recently had reportedly been a major money maker for News International, Murdoch's London newspaper publishing company.

A company spokeswoman declined to comment. The annual general meeting of Murdoch's main corporate vehicle, New York-based News Corp, is scheduled to be held on Friday in Los Angeles.