South Korea's anti-trust watchdog said Thursday that it approved Google's acquisition of Motorola Mobility with no conditions attached as the deal would not constrain competition in the mobile phone market.

"Based on international coordination (with other anti-trust watchdogs) and opinions from the parties concerned, we concluded that Google's takeover of Motorola Mobility will not restrain the competition in the related market," the Fair Trade Commission ( FTC) said in a statement.

Last August, the U.S.-based search engine giant clinched a deal to buy a 100 percent stake in Motorola Mobility, a maker of mobile phones with tens of thousands of patents essential for operating mobile phones. The U.S. firm notified the watchdog of the deal last December.

After probing into whether Google would abuse the patents owned by Motorola, the FTC ruled that the deal will not restrict competition in the handset industry as Google, the supplier of Android operating system (OS), would have no incentives to offer its OS only to Motorola with the low market share.

The watchdog noted that major rivals such as Apple and Microsoft held standard-essential patents (SEP) related to mobile phones, saying that the SEP holders were required by standard- setting bodies to follow the terms of fair, reasonable and non- discrimination (FRAND).

The anti-trust watchdog said that it will closely watch whether there would be any unfair practices such as abusive use of essential patents, adding that if so, it would take stern actions against the companies.