SAN FRANCISCO, April 17 (Reuters) - Microsoft, Facebook and more than 30 other global technology companies on Tuesday announced a joint pledge not to assist any government in offensive cyber attacks.

The Cybersecurity Tech Accord, which vows to protect all customers from attacks regardless of geopolitical or criminal motive, follows a year that witnessed an unprecedented level of destructive cyber attacks, including the global WannaCry worm and the devastating NotPetya attack.

“The devastating attacks from the past year demonstrate that cyber security is not just about what any single company can do but also about what we can all do together,” Microsoft President Brad Smith said in a statement. “This tech sector accord will help us take a principled path toward more effective steps to work together and defend customers around the world.”

Smith, who helped lead efforts to organize the accord, was expected to discuss the alliance in a speech on Tuesday at the RSA cyber security conference in San Francisco.

The accord also promised to establish new formal and informal partnerships within the industry and with security researchers to share threats and coordinate vulnerability disclosures.

The pledge builds on an idea for a so-called Digital Geneva Convention Smith rolled out at least year’s RSA conference, a proposal to create an international body to protect civilians from state-sponsored hacking.

Countries, Smith said then, should develop global rules for cyber attacks similar to those established for armed conflict at the 1949 Geneva Convention that followed World War Two.

In addition to Microsoft and Facebook, 32 other companies signed the pledge, including Cisco, Juniper Networks, Oracle, Nokia, SAP, Dell and cyber security firms Symantec, FireEye and Trend Micro.

The list of companies does not include any from Russia, China, Iran or North Korea, widely viewed as the most active in launching destructive cyber attacks against their foes.

Major U.S. technology companies Amazon, Apple, Alphabet and Twitter also did not sign the pledge.