American fans at the Ryder Cup "probably crossed the line" with their abuse of the European team, says the USA's Collin Morikawa.

Europe's victory in New York last month came amid torrents of verbal abuse from the home crowd.

Rory McIlroy was the main target of the abuse, while his wife Erica was hit by a drinks cup thrown from the stands.

The Northern Irishman described some of the behaviour as "unacceptable".

"There's a line that needs to be drawn. We have to learn how to find that division of what's appropriate and what's not," said Morikawa.

Europe won 15-13 to claim their first Ryder Cup triumph on American soil since 2012.

Before the tournament 28-year-old Morikawa, a two-time major winner, called on fans to "create absolute chaos".

He said this week: "Ryder Cups are meant to have a lot of energy and me saying the word 'chaos', I didn't mean for them to be rude.

"That's not on me, I believe, to take credit for people being rude."

McIlroy backed out of a putt at one stage because of the abuse and in a separate incident swore at a spectator who called out while he was addressing the ball.

Morikawa's team-mate Xander Schauffele said "unsavoury things" were said on the course.

"I really wish we could have played better to have them cheer for us a bit more," said Schauffele.

"New York's a tough place to play for anyone. I even got a few comments to play better."

American great Tom Watson, who captained the US at the 1993 and 2014 Ryder Cups, said last month that he was "ashamed" of the unruly scenes.

PGA of America chief executive Derek Sprague said this month that he would apologise to McIlroy and the rest of the European team.