Rocco Ritchie blocks Madonna on Instagram - report

Rocco Ritchie's strained relationship with his mother Madonna has intensified after it emerged he has blocked her from seeing his profile on Instagram.com, according to a report.

The teenager has around 138,000 followers on his social media account, which he keeps private, meaning fans have to ask permission to follow him.

Editors at British newspaper The Sun on Sunday report the 15-year-old has blocked his superstar mother from seeing his posts, and has even stopped following her profile on the site. However, his father, director Guy Ritchie, and stepmother Jacqui Ainsley have not been blocked.

"It's not a great sign that Rocco is blocking his mom on social media," a source tells the newspaper. "Hopefully this is just a teenage teething problem."

Madonna is currently locked in a bitter custody battle with her ex-husband Guy over where their teenage son should live after he reportedly refused to return to his mother in New York over Christmas.

The singer went to the Manhattan Supreme Court in an effort to get a judge to demand that Rocco return to the U.S. for the festive season, rather than spending it in the U.K. with his father and stepmother.

Despite the ongoing drama, Madonna posted a photo of her with her son on Instagram on Christmas Day, with the caption, "Merry X-mas to the Sun-shine of my Life! (sic)".

Madonna and Guy divorced in 2008 after almost eight years of marriage, during which they adopted another son, 10-year-old David Banda.

The Material Girl star is also mom to daughters Lourdes Leon, 19, and Mercy James, nine, while Guy has three young children with his new wife Jacqui, who he wed in July (15).