"While Greater China and other emerging markets accounted for the vast majority of the year-over-year iPhone revenue decline, in some developed markets, iPhone upgrades also were not as strong as we thought they would be", Cook wrote.
Apple on Wednesday lowered its revenue forecast to $84 billion for its first quarter ended December 29, below analysts' estimate of $88.05 billion.
The company said it now sees fiscal first-quarter revenue of $84 billion, below the $89 billion to $93 billion that it had previously expected.
Some analysts point to Apple's dependence on iPhone sales to drive revenue and profits, even as it tries to diversify its product base and add services such as music and digital payments.
Tariffs on imported smartphones, a ban on Apple Stores in India and the weakness of the Indian rupee against the U.S. dollar have hobbled the Silicon Valley giant.
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The spending package also includes a second measure that would extend funding for Homeland Security through February 8. Members of Congress left Washington while Trump remained at the White House and each side blamed the other.
Cook attributed much of the "shortfall" in the outlook to struggles in China that he pinned on the economy and "rising trade tensions" with the U.S. That sparked concern Apple wanted to avoid disclosing weak growth numbers.
"They're gonna be fine", Trump said at a Friday news conference at the White House.
Apple has warned that disappointing iPhone sales will cause a significant drop in its revenue over the crucial holiday season compared to earlier projections.
Archibald said the weaker outlook for China and weak US manufacturing numbers released Thursday will put pressure on the presidents of the world's two largest economies to make a deal faster to stop some of the economic uncertainty.
Wall Street did not take kindly to the news with Apple's shares tumbling 8% in after-hours trading to $145.15 a share after a momentary halt. Experts say many Chinese consumers are likely to reject Apple's iPhone price increases and instead buy less costly models from competitors.
The rare revenue warning - the company's first in almost 12 years - sent shockwaves through global financial markets with chipmakers that supply to Apple being the hardest hit.
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The sheriff said authorities don't have information that the gunman yelled anything to the victims during the shooting. After the shooting , Washington and her other daughters noticed Jazmine was unresponsive.
An advertisement for Huawei Mate 20 series is seen outside an Apple store, as customers queue before the store opens on the day the new iPhone XR goes on sale in Shanghai, China October 26, 2018.
Apple, indeed, has been hammered by China's lackluster growth and economic uncertainty posed by president Trump's tariff war.
Apple declined to comment on the group's statement but has previously said it believes its current phones comply with the Chinese court's order.
The warning, which came after trading in NY closed on Wednesday, looked likely to rattle already-volatile stock markets when they reopen on Thursday - with stock index futures pointing to Wall Street falls.
Which leads on to the next obvious question - How many iPhones are being junked or recycled just because they need a new battery?
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The Reds could have been in front early on, but Sadio Mane's shot rebounded from the post in the first half. Do we need an open something (wound)'. "Was it not? All right", Kompany told Sky Sports .