MILWAUKEE-- Johnson Controls has tendered an unsolicited, $1.25 billion offer for Visteon's automotive interiors and electronics businesses, but the bankrupt auto parts maker claims it is unclear of the bid's value to its shareholders.

The two companies are competitors, and Visteon said the bid is "highly conditional and vaguely defined." Visteon added that the offer complicates its attempt to win shareholder support for its reorganization plan.

"It is unclear at this point whether this proposal holds out any real prospect of enhancing value to Visteon's constituents," the company said in a published statement.

Visteon has been in bankruptcy court since May 2009. The company's finances are improving, however -- it turned a first-quarter net profit of $233 million -- and the bankruptcy court has extended the company's deadline for its reorganization plan.