Romanian star Larisa Iordache made a tearful exit from the World Artistic Gymnastics Championships on Wednesday after suffering an injury during a warm-up, ending her hopes of all-around gold.

The 21-year-old from Bucharest had been considered one of the favourites for the all-around title in Montreal in the absence of reigning champion Simone Biles of the United States.

Iordache was seen in tears as she was led out of the competition arena in a wheelchair after sustaining the leg injury during a warm-up for the floor exercise.

The International Gymnastics Federation (FIG) later cited the Romanian Gymnastics Federation as saying that Iordache had suffered a torn Achilles tendon.

Iordache won the all-around bronze medal at the 2015 World Championships in Glasgow and had earned a silver in the same discipline in Nanning in 2014.

She missed out on competing at last year's Rio de Janeiro Olympics after breaking a finger in March.

Iordache's withdrawal on Wednesday further depletes the women's field, already missing Biles and several other stars of the USA Olympic team.

Biles was among several gymnasts to send messages of support to the downcast Iordache.

"Praying for you @Larisa_Iordache. Keep your head up babe sending my love," Biles wrote on Twitter. "Don't ever give up girl you're amazing & inspiring."

"So sad for @Larisa_Iordache hang in there," Biles' USA team-mate Aly Raisman wrote on Twitter. "You will get through this. Sending you so much love."

Iordache's exit is one of several injuries which have struck competitors this week.

On Monday, Japanese star Kohei Uchimura, the six-time defending world all-around champion was injured in qualifying and withdrew.

Brazil's Rebeca Andrade, another seen as a possible medal contender in the women's all-around, suffered a knee ligament injury and also withdrew.

With Iordache out, Japan's Mai Murakami led qualifying for the all-around final with 55.933 points after Wednesday's final subdivisions.

Ragan Smith of the United States qualified in second place with 55.932 while Ellie Black of Canada was third with 55.766, raising hopes of a podium for the host nation.

Elsewhere Thursday, the qualifiers for the apparatus finals saw Uzbekistan veteran Oksana Chusovitina boon her place in the vault final.

Chusovitina, 42, is competing in Montreal fully 26 years after her first appearance in a world championships.

The men's individual all-around final takes place on Thursday with the women's medals decided on Friday. The apparatus finals take place on Saturday and Sunday.

 Source: AFP