Siemens is challenging General Electric’s bid to buy Alstom, setting up a trans-Atlantic power struggle that could either create a new supergiant in smart grid technology, or be scuttled by regulatory and political pressure.

That’s the latest update from Paris, where talks over the fate of the French power, train and grid giant were disrupted by Siemens’ offer of a cash and asset-swap deal valuing Alstom at 10 billion to 11 billion euros ($13.8 billion to $15.2 billion).

Last week, Bloomberg reported that GE was ready to pay $13 billion for Alstom’s power generation and transmission businesses, with potential plans to spin out its transportation division, maker of the TGV high-speed train. The news sent shockwaves through the French government, which paid 2.2 billion euros ($3 billion) to bail out Alstom in 2004, and considers its independence part of its national interest.

Sunday talks planned between French president François Hollande and GE CEO Jeffrey Immelt were rescheduled to Monday, the New York Times reported, after Siemens came in with its own plan. As reported by the Wall Street Journal, the April 26 letter from Siemens CEO Joe Kaeser describes combining some of Siemens' rail systems business with Alstom’s, while taking on Alstom’s grid business.

The move, which some commenters likened to creating an “Airbus” of energy and rail transportation out of the two companies, could satisfy French officials worried about giving control to a U.S. rival. At the same time, a Siemens bid could face antitrust scrutiny alongside GE’s proposal.

Alstom is the world’s third-biggest maker of gas turbines behind GE and Siemens, and the third-biggest transmission grid equipment maker behind Siemens and ABB. Its grid technologies include transmission grid equipment and software, substation automation systems, distribution grid control and asset management software. It’s also doing interesting work with Cisco and Itron in integrating multiple smart grid platforms via common networking and distributed computing concepts.

Alstom shares were suspended from trading Friday, and on Sunday the company requested they remain suspended as it prepares to comment on its future plans as early as this evening.