US regulators probe Motorola licensing US regulators have opened a new front in their antitrust investigations into Google, launching an inquiry into technology licensing practices at recently acquired mobile handset company Motorola Mobility. Meanwhile, in an intensification of the legal battles sweeping the smartphone industry, a US judge on Friday sided with Apple by issuing a preliminary injunction blocking imports into the US of a smartphone made by Samsung. Coming in the wake of a significant ban on a Samsung tablet earlier this week, the blocking of the Galaxy Nexus phone is the most significant blow Apple has yet struck in its wide-ranging legal fight with its South Korean rival. The US antitrust investigation of Motorola Mobility and preliminary injunction against Samsung are the latest indications of intensification in the legal battles that have broken out over the booming smartphone and tablet markets. Google and some of its competitors have received subpoenas from the Federal Trade Commission in recent days over Motorola patent licensing terms, according to two people familiar with the situation. Microsoft confirmed that it had been sent one of the FTC's formal requests for information, known as a civil investigative demand, but refused to comment further. The investigation is centred on whether Motorola has demanded excessive payments to license patents that other companies involved in the mobile industry are forced to use, according to one person who has seen a copy of the subpoena. So-called standards-essential patents, which are adopted by industry standards bodies and become common technology that all companies in the market must use, are generally required to be licensed on less stringent terms than other patents. A Google spokesperson said: "We take our commitments to license on fair, reasonable and non-discriminatory terms very seriously and are happy to answer any questions." The company refused to confirm that it had received a subpoena. Accusations that Motorola takes too hard a line on licensing its technology have already come under scrutiny in Brussels, where regulators have opened a wider review into whether standards-essential patents are being used by some companies to block competition. Motorola has also been criticised for using aggressive legal tactics over these patents. When acquiring patents from Nortel Networks earlier this year, Microsoft and Apple each gave a public undertaking not to sue others to enforce their rights if the technology was included in standards. However, Motorola refused to give a similar commitment over patents it was buying, drawing a rebuke from the US Department of Justice.