Cree on Thursday called off the $850 million sale of its Wolfspeed power business to Germany-based Infineon, citing the companies’ inability to satisfy U.S. concerns about security.

As a result, Cree will be paid a $12.5 million termination fee by Infineon.

Cree Chairman and CEO Chuck Swoboda says that Wolfspeed will remain part of Cree and that Cree will invest additional resources to grow the business.

“We are disappointed that the Wolfspeed sale to Infineon could not be completed,” Swoboda said in a statement.

“In light of this development, we are going to shift our focus back to growing the Wolfspeed business. The Wolfspeed business has performed well this year as our customers have further realized the value of our unique technology and is on a great path as a part of Cree.

“The strength of our balance sheet and improving operating cash flow gives us the ability to invest in Wolfspeed, while continuing to pursue our LED and Lighting growth plans. We believe investing to grow all three businesses will create the most value for our shareholders.”

Earlier Thursday, Infineon warned for the second time in a week- this time in words direct from its CEO and a board member – that the purchase of the Wolfspeed semiconductor power business might be blocked by the U.S. government.

Reuters news service said that Chief Executive Officer Rheinhard Ploss of Infineon, a global semiconductor manufacturer, told shareholders that there is “a very significant risk that we will not be able to complete the takeover as planned or possibly even at all.”

Reuters also reported that management board member Helmut Gassels also told the meeting: “We are in discussions with Cree about what could work to address the issues of CFIUS. But we think that this will be very unlikely.”

Ploss and Gassels made the comments at an Infineon shareholders meeting in Munich, Germany.

Cree (Nasdaq: CREE) and Infineon issued a similar warning last week. However, Infineon had said there might be ways to push the deal to closing.

The Committee on Foreign Investment in the United States, or CFIUS, has expressed security concerns about the sale, but those have not been specified. Hower, Reuters reports that Ploss told shareholders that CIUS had not suggested any possible ways to address concerns.

​The deal was announced in February 2016.