A petition calling for soldiers involved in Bloody Sunday to be granted immunity from prosecution has gained more than 20,000 supporters in three days.
A protest march against the police investigation of the former paratroopers who killed 14 civil rights demonstrators in Londonderry in 1972 is also being planned in London for later this month.
The moves come after the arrest of the first solider by detectives conducting a murder probe into the events of what was one of the most notorious days in the Northern Ireland Troubles.
The 66-year-old detained in Co Antrim on Tuesday was released on police bail on Wednesday night.
His arrest was welcomed by bereaved relatives of those killed.
In London, a High Court judge is considering whether seven other former paratroopers involved on Bloody Sunday are entitled to launch a legal challenge against the police investigation.
The seven - referred to as B, N, O, Q, R, U and V - want to challenge the way in which Police Service of Northern Ireland (PSNI) detectives are conducting their historical inquiry.
The on-line petition is in the form of a request to Home Secretary Theresa May to "grant legal pardons for all troops involved in Bloody Sunday".
It states: "This petition calls for all arrests and investigation into Forces veterans during the Troubles to cease forthwith and the soldiers who were present on that fateful day to be exonerated in the same way that members of known Republican terror groups have been exonerated for their terrorist crimes."
The petition goes on to say "no benefit" comes from "persecution" of veterans and insists most people in Northern Ireland have "moved on and want to forget".
It adds: "These political statements to appease the Republican/Sinn Fein movement must stop."
Thirteen people were killed by members of the Parachute Regiment on the day of the incident in Derry's Bogside. Another victim of the shootings died in hospital four months later.
Northern Ireland police launched the murder investigation in 2012. It was initiated after a Government-commissioned inquiry, undertaken by Lord Saville, found that none of the victims was posing a threat to soldiers when they were shot.
Following the publication of the Saville report in 2010, Prime Minister David Cameron apologised for the Army's actions, branding them "unjustified and unjustifiable".
In September, the PSNI told bereaved families they intended to interview a number of former soldiers about their involvement on the day.
Nigel Kelsall is organising the protest march in London in support of the former paratrooper arrested and bailed by police earlier this week.
Mr Kelsall was 18 when he was sent to Northern Ireland on his first operation in 1994.
The army veteran, who has also signed the 20,000-strong petition calling for immunity for Bloody Sunday soldiers, said he was hoping for "crowds in their thousands" to join him on the streets.
The 40-year-old from Essex said of the latest arrest: "We are not too happy about the way he is being treated. At the time when he was in Northern Ireland he was following orders, being told what to do.
"To pull him in now after all this time is a disgrace from our government, especially as they have been releasing IRA terrorists.
"We want to show a presence on the ground and that we do not want this to happen to me or you or the next person.
"We want to show our country that we stand together."
He said that he had also been asked to set up marches in Scotland and Northern Ireland to mirror the London protest.
The march is expected to start at around 10am on Saturday November 21. The exact route has not been confirmed, but marchers are due to congregate for a two-minute silence at the Cenotaph war memorial in central London.