Apple has found itself in hot waters, yet again. The battery of some of its iPhone 5S models is draining out fast due to a manufacturing defect  The tech giant is making vigorous efforts to replace all affected phones.

Apple had a successful launch of its iPhone lineup with the 5S and 5C models. Although the iPhone 5C lagged behind 5S, together both models set a new record of selling 9 million units in the opening weekend. The new OS on the latest iPhone drew heavy criticism from its users, but the iPhone 5S proved itself the company's best smartphone.

Along with a slew of new features, Apple also promoted iPhone 5S as having significantly longer battery life compared to its predecessors. However, some users were in for a surprise when their iPhones' did not last as long as it was promised. Apple quickly investigated the issue to find out that the problem was a manufacturing defect that caused the battery to drain quickly.

"We recently discovered a manufacturing issue affecting a very limited number of iPhone 5S devices that could cause the battery to take longer to charge or result in reduced battery life," Teresa Brewer, an Apple spokeswoman, told the New York Times. "We are reaching out to customers with affected phones and will provide them with a replacement phone."

The company did not comment on the number of affected smartphones but the report suggested "a few thousand" phones to be suffering from the defect.

Apple iPhone 5S went on sale September 20, and was advertized to have a battery life of up to 10 hours talk time and 250 hours on standby.