Britain's competition regulator said on Tuesday it has launched a "Phase 1" probe into Amazon.com Inc's planned $1.7 billion acquisition of iRobot Corp, which makes the Roomba vacuum cleaner.

The probe launch by the UK watchdog comes at a time antitrust regulators, including those in the U.S. and the European Union, have become increasingly wary of giant companies acquiring smaller rivals.

The Amazon-iRobot deal – announced in August last year to expand the company's stable of smart home devices – is already being reviewed by the U.S. Federal Trade Commission (FTC).

Amazon, along with Microsoft, is currently facing an antitrust investigation in Britain after the communications regulator said some aspects of the cloud market, including fees to switch supplier, were a cause for concern.

Responding to a Reuters request for comment, Amazon said the company was working cooperatively with the relevant regulators in their review of the merger.

An iRobot spokesperson told Reuters that the firm continued to cooperate with both the U.S. FTC and other regulatory agencies.

UK's Competition and Markets Authority (CMA) said it had until June 16 to make its decision on whether the Amazon-iRobot deal will reduce competition in the UK.

(Reporting by Aby Jose Koilparambil and Sinchita Mitra in Bengaluru; Editing by Savio D'Souza and Louise Heavens)