A renowned rock climber scaled New Jersey's tallest residential tower on Friday, using nothing but his hands and feet to ascend the exterior of the 69-story, 713-foot-tall Urby apartment building on the Jersey City waterfront.

Alex Honnold, the only person ever to have solo free-climbed Yosemite National Park's famed El Capitan, began his climb up the tower just after midnight on Friday morning.

Honnold, a 33-year-old native Californian, announced the ascent on his Facebook page.

I spent the night climbing on a sky scraper, had a fun session at the climbing gym and bought my first suit. All in all a pretty legit day in the city! Ready for the next round of film festivals. . . Posted by Alex Honnold on Friday, September 7, 2018

"I spent the night climbing on a skyscraper, had a fun session at the climbing gym and bought my first suit," Honnold wrote in the post. "All in all a pretty legit day in the city!"

In his own Facebook post, Honnold embedded an Instagram post by The New Yorker that included a photograph of him clinging to the glass tower high above Jersey City's skyscraping waterfront, with the Hudson River and New York Harbor beyond.

A story on The New Yorker website said Honnold made it half-way up the Urby.

Honnold is at the pinnacle of the free-climbing world, that is, the community of climbers who forego ropes, pitons and other equipment on ascents, and prefer to make their way up using only their hands, feet and the existing holds on the surface of the rock faces or buildings they ascend.

The University of California at Berkeley dropout has achieved many firsts in climbing and has been honored by the American Alpine Club and other groups for his contributions to the sport. Honnold chronicled his solo ascent of El Capitan in his book, "Alone on the Wall," co-written with David Roberts.

Jersey City Mayor Steven Fulop had been in touch with Honnold and tweeted that he heard from the alpinist in the middle of his overnight ascent on Urby.

He texted me at 230am that he was half way up + was going to sleep on one of the ledges and was going to enjoy the views. @AlexHonnold @charlesbethea #urby pic.twitter.com/sU8O2UYCM5 — Steven Fulop (@StevenFulop) September 7, 2018

A Jersey City spokeswoman, Kimberly Wallace-Scalcione, offered an assurance Saturday that authorities had been well aware of what was happening, and the event was not uncontrolled.

"The JCPD and mayor were in the loop the entire process," she said in an email.

Steve Strunsky may be reached at sstrunsky@njadvancemedia.com. Follow him on Twitter @SteveStrunsky. Find NJ.com on Facebook