A Florida high school student shot and wounded a classmate on Friday as students around the United States staged walkouts to protest gun violence.

The Sheriff's Office for Marion County said the suspect was in custody following the early morning shooting at Forest High School in Ocala, Florida.

The Ocala Star Banner newspaper said one student shot another in the ankle.

The Florida shooting came as students nationwide were walking out of classes to mark the 19th anniversary of the 1999 carnage at Columbine High School in Colorado which left 13 people dead.

The walkout has been organized by students at Marjory Stoneman Douglas High School in Parkland, Florida, where 14 students and three adult staff members were killed by a troubled former classmate on February 14.

The Parkland students have spearheaded a grassroots campaign for gun control which included marches by hundreds of thousands of Americans on March 24.

"So proud of the #NationalSchoolWalkout and all of the students around the country who are standing up for positive change and demanding what we deserve," tweeted Cameron Kasky, a Parkland student leader.

In Washington, several hundred students from area high schools rallied outside the White House and then marched on Congress to demand action on gun control.

Carrying signs reading "Enough Is Enough" and "Books Not Bullets," they chanted "We will vote" as they marched.

- 'Change needs to happen' -
"A lot of people from my school came to show our support for increasing safety at schools and for better gun control legislation," said Matt Compton, a 15-year-old at Bethesda-Chevy Chase High School in Maryland.

"I will vote for someone who I think will help solve this issue when I'm old enough," Compton said.  

"I feel like things have gotten worse these last few years," said Emma Corcoran, also a 15-year-old from Bethesda-Chevy Chase High School. "Change needs to happen."

Former Arizona congresswoman Gabby Giffords, who was shot and seriously wounded by a gunman in 2011, sent a series of tweets supporting the students.

"After Columbine, America's politicians said, 'never again.' But after nearly two decades of inaction, it's clear they've failed in their basic duty to keep our kids safe," Giffords said.

"They are warning politicians to show the courage to address our gun violence or get voted out," she said. 

In New York, Arielle Geismar, 16, a co-founder of "NYC Says Enough," told CNN students are "taking action."

"We're taking to the streets," Geismar said. "Most of us can't even vote yet, but we're working extremely hard to make sure that no one has to suffer the way that people have."

Meanwhile, an ABC News/Washington Post poll showed that support for a ban on assault weapons has risen sharply in the past few months.

Sixty-two percent of those polled said they support a nationwide ban on the sale of assault weapons, up from 50 percent in mid-February and 45 percent in late 2015.

Seventy-one percent of those surveyed said Congress is not doing enough to try to prevent gun violence and 59 percent said that President Donald Trump is not doing enough.