CUPERTINO, California — Apple CEO Tim Cook defended his company's opposition to the FBI's iPhone-hacking plan at its annual shareholder meeting, one day after the tech giant formally challenged a court order to help the FBI unlock an encrypted iPhone used by a murderous extremist in San Bernardino, California.

"We do these because these are the right things to do," Cook said in a brief reference to the company's privacy stance in the case.

Major tech companies are also rallying to Apple's cause, and now plan a joint "friend of the court" brief on its behalf. Facebook said it will join with Google, Twitter and Microsoft on a joint court filing. A Twitter spokeswoman confirmed that plan, but said that different companies and trade associations will likely file "multiple" briefs.

Federal officials have said they're only asking for narrow assistance in bypassing some of the phone's security features. But Apple contends the order would force it to write a software program that would make other iPhones vulnerable to hacking by authorities or criminals in the future.

Apple filed court papers on Thursday that asked U.S. Magistrate Sheri Pym to reverse her order on the grounds that it over-reached the government's legal authority by forcing the company to weaken the security of its own products. The company accused the government of seeking "dangerous power" through the courts and of trampling on its constitutional rights.

The dispute raises broad issues of legal and social policy, with at least one poll showing 51 percent of Americans think Apple should cooperate by helping the government unlock the iPhone.

But it's unclear how the controversy might affect Apple's business. Analysts at Piper Jaffray said a survey they commissioned last week found the controversy wasn't hurting the way most Americans think about Apple or its products.

At least one shareholder at Friday's meeting voiced support for the company's stance.

"Apple is 100 percent correct in not providing or doing research to create software to break into it," said Tom Rapko, an Apple investor from Santa Barbara, California, as he waited in line to enter the auditorium at Apple's headquarters. "I think if you give the government an inch, they'll take a yard."

The company also received support from the Rev. Jesse Jackson and a representative from the Electronic Frontier Foundation, an Internet rights groups.

"We applaud your leadership," Jackson, a longtime civil rights leader and former adviser to Martin Luther King Jr., told Cook. "I recall the FBI wiretapping Dr. King in the civil rights movement," he added. "We cannot go down this path again. Some of us do remember the days of (former FBI director J. Edgar) Hoover and McCarthy and Nixon and enemies lists."

Apple's share price has seen little change since the issue erupted in the news last week. Overall, though, the company's stock has declined in recent months over worries that iPhone sales were slowing around the world.

A hearing on the iPhone legal dispute is scheduled for next month.

Associated Press writers Eric Tucker and Tami Abdollah in Washington and Bree Fowler in New York contributed to this report.