Twitter is facing a patent infringement lawsuit in the States as a Texas-based company, TechRadium, is claiming the micro-blogging site has pinched tech from its patents.

TechRadium offers "mass notification and emergency alerting systems" to government, commercial and educational clients.

TechRadium claims Twitter's tweeting messaging system is based on three of its patented "immediate response information system" digital-notification technologies.

Filed to the US District Court for the Southern District of Texas, the suit is asking for "recovery of damages for lost profits, reasonable royalties, unjust enrichment, and benefits received by the Defendant as a result of use of the misappropriated technology".

TechRadium's lawyer told the IDG News Service that: "The problem is the Twitter architecture. The way they have it set up is technology that is squarely within TechRadium's patents".