There have been renewed calls for stricter gun control in the United States following the shooting deaths last week of 14 students and three adults at a Florida high school.

Demonstrators participate in a
Demonstrators participate in a "lie-in" during a protest in favor of gun control reform in front of the White House. Grassroots groups are planning hundreds more protests in coming weeks. (AP)

Busloads of Florida students headed on Tuesday to the state capital Tallahassee to call for a ban on assault rifles, pressing on with protests after a shooting rampage at a high school that killed 17 teens and educators.

Last week's killing, the second-deadliest shooting at a public school in US history, has inflamed a national debate about gun rights and prompted teens from Marjory Stoneman Douglas High School and across the US to demand legislative action. 

The incident has galvanised advocates for stricter gun controls, including many survivors of the shooting.

A Washington Post/ABC News opinion poll released on Tuesday showed that 77 percent of Americans believe the Republican-controlled Congress is not doing enough to prevent mass shootings, with 62 percent saying President Donald Trump, also a Republican, has not done enough on that front.

Students who survived the shooting have promised they will push for action. Jaclyn Corin, a 17-year-old junior at the school in Parkland near Fort Lauderdale, said on Twitter that she had secured a meeting with Florida's Republican Governor, Rick Scott, on the issue.

Scott spokeswoman Lauren Schenone confirmed the governor would be "meeting survivors later this week."

Nikolas Cruz, 19, is accused of returning to the high school from which he had been expelled and opening fire with a semiautomatic AR-15 assault rifle on Feb. 14. He faces 17 counts of premeditated murder.

Students, many of whom have grown up in a world where they regularly train for the possibility of being targeted by a shooter on the loose, teachers and gun safety advocates were due to gather in Tallahassee on Wednesday to demand that state lawmakers enact a ban on the sale of assault weapons in Florida.

Gun ownership is protected by the Second Amendment of the US Constitution and remains one of the nation's more divisive issues. 

The Washington Post/ABC News poll found that fewer than seven in 10 Republicans support the idea of a ban on assault weapons, the reverse of Democrats, 71 percent of whom support it. A federal ban on assault weapons, in force for 10 years, expired in 2004.

The suspect, whose mother died in November, was investigated by authorities after videos surfaced on the social media platform Snapchat, showing him cutting himself, an assessment by Florida's Department of Children and Families said.

The Federal Bureau of Investigation has acknowledged it failed to act on a tip that was called in last month and that warned that Cruz possessed a gun and the desire to kill.

Source: Reuters