OAK BROOK, Ill. – McDonald's Corp. began allowing customers to customize their burgers in an effort to generate excitement for its products, according to news reports.

McDonald's has been pressured by lagging sales in the United States and abroad. the company reported a 3.7 percent decline in global comparable sales for August, while sales at existing stores in the US declined 2.8 percent. The company plans to address the issue through service, value and menu opportunities to boost customer loyalty.

News reports state that McDonald's launched the test of a build-your-own burger concept in hopes of pin-pointing popular combinations that the chain can later implement at its other restaurants. Currently, the test is underway at four locations in Southern California.

McDonald's is collaborating with Apple on the tech giant's new mobile payments system called Apple Pay.

In other McDonald's news, the chain also announced it will accept Apple Pay in all of its US restaurants. Customers using iPhone 6, iPhone 6 Plus or Apple Watch can access Apple Pay through McDonald's near-field communication payment scanners. Customers' payments will be charged to credit or debit cards on file in their iTunes account.

“Apple Pay enhances our global digital strategy and is a win for McDonald’s customers who desire greater speed and ease,” said Atif Rafiq, McDonald’s senior vice president and global chief digital officer. “Apple’s transformative mobile payments service brings a new level of convenience to McDonald’s customers, allowing them to instantly pay and stay, or pay and be on their way. Our support of mobile payment options further demonstrates our commitment to be an influential leader in the retail digital space.”