TORONTO -- Google is adding two new smartphones to the growing number of iPhone alternatives scheduled to hit shelves before the start of the busy holiday shopping season.

Both the Nexus 5X and Nexus 6P were unveiled by Google on Tuesday, with the technology giant saying they are the first smartphones to use "Marshmallow," Android's latest update of its operating system.

The phones, which will be available before the end of October, come amid a highly competitive year in the Canadian wireless industry.

In July, the CRTC eliminated cancellation fees for wireless contracts after two years, effectively releasing a large number Canadians from three-year phone contracts and giving them the ability to move to other telecommunications providers.

The rule change could give the Nexus phones an advantage against competitors because all of the models are unlocked devices, which means they're not tethered to one specific wireless carrier.

"The competitiveness and nature of this market continues to evolve every day," said Darren Seefriend, head of Android Partnerships at Google Canada.

The Nexus 5X has a 5.2-inch screen and starts at $499 Canadian for a 16GB phone without a contract, while the Nexus 6P has a 5.7-inch screen and starts at $699 for a 32GB device.

But they've going to be facing some formidable competition from a raft of other smartphone makers.

On Monday, Apple Inc. reported that first weekend sales for its latest smartphones set records for the company. Apple sold more than 13 million iPhone 6s and 6s Plus phones in the first three days after the launch, it said.

That was well above the 10 million iPhone 6 and 6 Plus models that flew off shelves last year, though this year China was included in the sales numbers for the first time.

Samsung headed off the competition by launching its larger-screened Galaxy Note 5 and S6 Edge+ in August.

BlackBerry (TSX:BB) is expected to jump into the fray later this year with the release the BlackBerry Priv, its first phone to run on Google's Android operating system.

Among the other announcements, Google also launched the second generation of Chromecast, a video stick that plugs into the back of a television and allows users to stream services like Netflix, CraveTV and Shomi from a laptop to a bigger screen.

The updated Chromecast redesigns the casing into a round disc shape from its original stick size, a change which the company says is better for connectivity. The new version also introduces a feature called Fastplay, which pre-loads video content while the user is still browsing through streaming services, with the goal of making it faster to jump to a new program.

Google also released Chromecast Audio, a version of the device specifically for wirelessly streaming music to a standard speaker. Chromecast Audio supports a variety of streaming music services, including Google's Play Music and Spotify.

One of the standout features of Chomecast Audio overcomes a major setback of Bluetooth technology -- which is a popular way for users to wirelessly connect to a speaker. With the Chromecast, they can link their smartphone to the speaker for music, but continue to separately use the same phone to make calls or record video without interrupting the audio.

Both Chromecast devices sell for $45 and were released in stores on Tuesday.