Apple Inc Chief Executive Steve Jobs on Thursday called Adobe Systems Flash multimedia software a closed system that is ill-suited for the company's suite of mobile devices, escalating the war of words between the two companies.

Jobs said Flash's system is closed because it is a proprietary system from Adobe, which controls everything from its features to its pricing. Ironically, perhaps, similar charges have been lobbed at Apple's products and services, such as iTunes.

In a long, detailed letter posted on Apple's website, Jobs cited a number of problems with Flash, which is used to run video on many Internet sites but which is not compatible with Apple's iPhone and iPad.

Adobe has characterized our decision as being primarily business driven - they say we want to protect our App Store - but in reality it is based on technology issues. Adobe claims that we are a closed system, and that Flash is open, but in fact the opposite is true, he said.

Jobs went on to detail a list of complaints about Flash, raising questions about its security, technical drawbacks, and power-management.

Flash is a successful business for Adobe, and we can understand why they want to push it beyond PCs, he said. But the mobile era is about low power devices, touch interfaces and open web standards - all areas where Flash falls short.

Adobe was not immediately available for comment.

Shares of San Jose, California-based Adobe fell 2 percent to $34.72 in midday trading on the Nasdaq. Shares of Cupertino, California-base Apple rose 2.4 percent to $267.91.

(Reporting by Gabriel Madway)