Toronto-Dominion Bank's online and mobile banking platforms in the U.S. are experiencing technical difficulties after a recent upgrade, prompting customers to complain on social media.

Several of the Canadian lender's U.S. clients have taken to Twitter to complain about problems accessing their accounts online or on the mobile app, issues which surfaced late last week after TD rolled out a technical update.

TD Bank, whose slogan south of the border is "America's Most Convenient Bank," on Saturday posted a statement on its website apologizing to clients for the inconvenience.

It did not immediately respond to requests for comment, but the bank's official U.S. Twitter account told clients early this morning that it had been experiencing an online outage.

By late morning, TD Bank's U.S. Twitter account informed some users that its technical department had indicated that all platforms for online banking are available.

This comes after TD's online brokerage platform faced outages in late 2017 and earlier this year amidst an "unprecedented" surge in trading volumes.

The bank's e-transfer service also experienced some issues in November after a transition to a new platform.