Apple chief executive Steve Jobs took his case against Adobe's Flash software public on Thursday, arguing that the product is a flop on touchscreen gadgets such as the iPhone and iPad.

"Flash was created during the PC (personal computer) era for PCs and mice," Jobs said in an open letter posted at the Cupertino, California-based firm's website.

"But the mobile era is about low power devices, touch interfaces and open Web standards -- all areas where Flash falls short," Jobs said.

Adobe boss Shantanu Narayen fired back calling the criticisms "a smokescreen" in a Wall Street Journal interview live-blogged online.

Apple appears irked about Flash being designed to work across multiple platforms, including those of rivals such as Google with its open-source Android software, according to Narayen.

"We have different views of the world," Narayen said. "Our view of the world is multi-platform."

Jobs complained that relying on Flash would shackle program developers to software designed to work on many platforms instead of crafted to excel on Apple gadgets.

"It is not Adobe's goal to help developers write the best iPhone, iPod and iPad apps," Jobs said.

"It is their goal to help developers write cross platform apps. And Adobe has been painfully slow to adopt enhancements to Apple's platforms."

Narayen countered that Apple's ban of Flash puts developers through the hassle of having to create multiple versions of applications instead of making one program that works on different devices.

Online videos and games are commonly based on Flash, and Apple's refusal to allow Flash on its iPod, iPhone and iPad devices has been a sore point with Adobe.

Lack of Adobe support has also been among top criticisms of Apple gadgets, which have been global hits nonetheless.

Jobs contended that most online video is available in formats other than Flash and therefore "iPhone, iPod, and iPad users aren't missing much video."

He conceded that Apple mobile gadgets don't play Flash-based online games but noted that thousands of games, many of them free, are available at the firm's App Store on the Internet.

"We have routinely asked Adobe to show us Flash performing well on a mobile device, any mobile device, for a few years now," Jobs said. "We have never seen it."

Apple's decision to bar Flash from its gadgets is technology-based, not a business decision aimed at safeguarding the App Store, as Adobe has insinuated, according to Jobs.

Apple devices instead support video built using HTML5, a fledgling software format created by a group of technology firms including Google and Apple.

Jobs also cited security concerns, saying Flash has a record when it comes to hackers exploiting the software and that Apple deems Flash the prime cause for Macintosh computer crashes.

"We don't want to reduce the reliability and security of our iPhones, iPods and iPads by adding Flash," Jobs said.

Narayen blamed any computer crashing troubles on Apple's operating software and not Adobe programs.

Video done in Flash also devours power, cutting precious battery life in mobile devices, according to Apple. Narayen dismissed the claim as "patently false."

"Perhaps Adobe should focus more on creating great HTML5 tools for the future, and less on criticizing Apple for leaving the past behind," Jobs said.

Narayen countered that this is an "incredibly productive time" and that the California company's "innovation is blowing people away."

He expressed confidence that Adobe's multi-platform approach to software wold "eventually prevail" and said he is for "letting customers decide."

The Adobe chief executive also noted that he uses a Nexus One smartphone from Google, not an iPhone.