Apple Inc. is releasing a thinner and lighter iPhone at the end of September, hoping to cut off Samsung Electronics Co. and other manufacturers looking to fill the "vacuum" prior to the release of the iPhone 5.

Lorraine Luk and Yukari Iwatani Kane at The Wall Street Journal, citing people familiar with the situation, said the new iPhone is expected to be similar to the current iPhone 4, but slimmer with an improved eight-megapixel camera. Apple is aiming to release it by the end of September, according to the report. The WSJ added the new iPhone will operate on Qualcomm Inc.'s wireless chips, replacing chips provided by a former unit of German chip maker Infineon Technologies AG.

Bloomberg News, quoting two people familiar with the plans, reported last month that the iPhone 5 will closely resemble the iPhone 4 in some ways but will have a more powerful chip and a more advanced camera. It said iPhone 5 will have a A5 processor, a more powerful chip that was added to the iPad 2, which was released in April. The iPhone 5 will also have an 8-megapixel camera, up from the 5-megapixel model of the iPhone 4, according to the same sources cited by Bloomberg.

DigiTimes, citing Taiwanese component suppliers it didn't identify, said that Taiwanese notebook manufacturer Pegatron Technology has received orders for 15 million iPhone 5 units from Apple, with the units slated to start shipping in September of 2011.

The new iPhone has gained hype after Steve Jobs opted not to unveil the latest smartphone model at its annual developers' conference in June.

Apple has aggressive estimates for the iPhone 5. It is said to be targeting 25 million units by the end of the year.

Production problems have reportedly delayed the iPhone 5's launch. The WSJ said that a person briefed on Apple's product plans said the Cupertino, Calif.-based company had planned to release the new iPhone this summer, but the device wasn't ready in time. The drop date could again be delayed if Hon Hai Precision Co., which assembles the iPhone for Apple, couldn't improve its production yield rate, according to the WSJ, citing the same sources.

The delay of the iPhone 5 has benefited other phone manufacturers like Samsung Corp. Samsung is poised to surpass Nokia as the world's largest smartphone manufacturer this year as Nokia has not yet released its Microsoft Windows-based phones.

According to research firm International Data Corp., Apple was the second-largest manufacturer in the first quarter, with an 18.7% market share, selling 18.7 million units of the iPhone, just behind Nokia, which had a 24.3% share. Samsung's 10.8% market share was fourth, as it benefited from a 350% increase in sales year over year. Apple has not released a new smartphone this year.

Samsung aims to sell 60 million smartphone units before 2011 ends.It sold 10.8 million units in the first quarter. Samsung shipped 19.2 million units of such handsets in the second quarter, according to estimates by Charles Park, a Hong Kong-based analyst for Mizuho Securities Asia. Samsung reported this week that sales of the Galaxy S2 smartphone have reached 3 million since the release last May.

The sales of Samsung this year and other vendors like LG have pushed Google's Android operating system to become the top platform for smartphones.

Samsung and Apple are engaged in litigation. Apple this week filed a complaint with the U.S. International Trade Commission., seeking to block U.S. sales for Samsung smartphones and tablets.The move just a week after Samsung requested that the ITC stop importing iPhone and iPad that are manufactured in china.

"The Galaxy S line of mobile phones has been designed to look and operate like the iPhone, and it infringes on multiple Apple utility and design patents," Apple said in the complaint filed with the ITC.

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