* Break-up would be "totally wrong" - chairman in Die Zeit
* "We will not leave the field to locusts" - top investor
* Comments come after activist investors call for overhaul (Recasts, adds comment from the foundation, context)
By Christoph Steitz and Tom Käckenhoff
FRANKFURT/DUESSELDORF, July 11 (Reuters) - A break-up of Thyssenkrupp is out of the question, according to both its supervisory board chairman and top shareholder, taking aim at investors that have called for a radical overhaul of the German industrial group.
Speculation about Thyssenkrupp's future has intensified following the resignation of CEO Heinrich Hiesinger last week.
"I think this (a break-up) would be a totally wrong move," Chairman Ulrich Lehner told German weekly paper Die Zeit in an interview published on Wednesday.
He added there were no plans to divest the group's elevator unit, its most profitable business, which some investors and analysts have said would rid Thyssenkrupp's share price of a large conglomerate discount.
"Crown jewels ... are only sold in times of need. There is no need (at Thyssenkrupp)," Lehner was quoted as saying.
His comments appear directed at Cevian and Elliott, two of the company's largest shareholders, which criticised the steel-to-submarines group's performance under Hiesinger, including a 28-percent share price decline during his tenure.
Cevian, Thyssenkrupp's second-largest shareholder with a 18-percent stake, has been vocal in calling for a strategic review of all of Thyssenkrupp's business areas, saying each might thrive better in a different set-up.
The Alfried Krupp von Bohlen und Halbach Foundation, the group's biggest investor with a 21 percent stake and two seats on its supervisory board, said this would not happen.
"We will not leave the field to the locusts, otherwise we're betraying the foundation's mandate," Reimar Luest, its deputy chief, told Die Zeit in separate comments, referring to a term used in Germany for activist investors.
"If we could, we would bring back Mr Hiesinger immediately. We always stood behind him."
Hiesinger's resignation, which came only days after he clinched an historic steel joint venture deal with Tata Steel , followed months of shareholder pressure over the company's strategy.
"Much has been done in the public sphere to destabilise the company and him as a person," Lehner said, adding some shareholders were behaving in a way that could be described in part as "psychological terror".
He said that included spreading false statements in the public domain and making unjustified demands for management to resign. Lehner did not specify which statements and demands he was referring to.
Cevian declined to comment. Elliott had no immediate comment. (Editing by Maria Sheahan and Mark Potter)