The latest round of patent wars between smartphone players has seen Apple lose an interim ruling in the US, after the firm attempted to sue Motorola Mobility for infringing three of its patents.

The Administrative Law Judge in the US International Trade Commission (ITC) has ruled in favour of Motorola Mobility, after having found no violation for any of the three Apple patents listed in Apple’s suit.

Although the decision is yet to be ratified by the ITC, it is very rare for it not to uphold the Administrative Law Judge’s ruling. Apple, however, can appeal the preliminary ruling. The formal judgment to the case is expected to be given in May.

“We are pleased with today’s favourable outcome for Motorola Mobility,” said Scott Offer, senior vice president and general counsel of Motorola Mobility. “Motorola Mobility has worked hard over the years to develop technology and build an industry-leading intellectual property portfolio.”

Meanwhile, Apple has also publicly identified nearly all of its suppliers and invited an outside workplace conditions group to inspect them. The firm has come under scrutiny following reports of unethical practices and high rates of suicides at its suppliers, such as Foxconn.

Previously, the company had kept details of its supply chain secret, but it has now revealed a supplier responsibility report, which revealed that the company conducted 229 audits at different supplier factories over the past year, and found that employees at 93 factories had exceeded their “weekly working hour limits”, while there had been payment violations at 108 facilities and five factories had employed underage workers, though that was allegedly due to “insufficient controls to verify age or detect false documentation”.

Apple stated that it is working closely with its suppliers to ensure that these issues were resolved.