FRANKFURT, Germany (AP) -- Industrial union IG Metall has asked Siemens AG to reveal its plans for its share of a 50-50 joint venture in Fujitsu-Siemens Computers.

"This uncertainty has to finally have an end," said Juergen Kerner, the chief of IG Metall in Augsburg, where the computer unit has some of its German operations.

Kerner said Siemens employees were concerned about news reports that Siemens wants to sell its stake in the venture.

The reports said Munich-based Siemens was considering selling its stake to Fujitsu. A Siemens spokesman said Friday the company does not comment on speculation.

Tokyo-based Fujitsu has the first right of refusal to buy Siemens' 50 percent stake in the company.

Some news reports said China's biggest computer maker Lenovo Group Ltd. is interested in a stake.

In August Siemens Chief Executive Peter Loescher said the future of the venture was being discussed with the Japanese partners. He had previously indicated he was not happy with the unit's performance.

According to Siemens, FSC had revenue of 6.6 billion euros ($10.2 billion) and pretax profit of just 105 million euros ($123 million) in 2007.

The unit has 2,000 employees in production and administration in Augsburg alone, while FSC employs another 4,200 across Germany. Worldwide, FSC employs more than 10,000.

Kerner said a breakup of the company was unlikely, but the union would demand that past agreements are honored, and that German sites would be kept if it is sold off.

Shares of Siemens were up 4.4 percent at 45 euros ($60.75) in late Frankfurt trading Friday.