The number of US military flights landing at Shannon Airport soared by 15pc last year, new figures obtained by the Sunday Independent reveal.
The revelation comes amid growing anti-war sentiment and just two weeks after Independent TDs Clare Daly and Mick Wallace were arrested for breaching the security perimeter at the airport in protest at its use by the US military.
According to the figures, the Americans accounted for 95pc of all foreign military flights that landed at Shannon in the past 12 months.
The US military accounted for 630 of the total 666 foreign military flights granted permission to land at Shannon Airport.
This is an increase on 2012, when the Department of Foreign Affairs granted permission for 548 US military flights.
The increase in the number of military flights at Shannon comes amid heightened tensions in the Middle East and the Ukraine. The other countries to use the airport for military landings included: Italy (eight times), France (seven times), Canada (five times), Egypt (four times), Croatia (three times), Belgium (twice). Bahrain, Malaysia and Mexico each used the airport once to land military personnel at Shannon.
Though the numbers are down from a decade ago when the US's occupation of Iraq was at its most intensive, peace activists argue the continued extensive use of Shannon by the US military undermines Ireland's neutrality.
European Ombudsman Emily O'Reilly recently accused the Government of "turning a blind eye" to the use of Shannon airport by the US for rendition purposes.
Ms O'Reilly also raised the question as to whether Ireland has compromised on justice in order to maintain good relations with Washington.
In total, 70,000 armed US troops passed through Shannon Airport in 2013. Anti-war protest group Shannonwatch estimate that more than 2.25 million armed US troops have passed through Shannon Airport since 2002. The numbers peaked in 2005 when Shannon facilitated 341,000 soldiers on their way to war.
Separate figures obtained by the Sunday Independent show that almost 1,200 US flights were given permission to fly in Shannon's airspace by Irish authorities within the past year, out of a total of 1,546 military flights. Deputy Wallace has urged the Government to stop allowing Shannon to be used "as a US military airbase". He said at the time of his arrest: "The Government must search planes if they want to stop Shannon Airport being used as a military airbase."
The use of Shannon by the US military has long been a source of controversy, particularly over persistent allegations that the airport was used as a stopover for so-called rendition flights.
It was alleged some flights passing through the airport, which serves the west of Ireland, were used to transport US prisoners to locations at which they were subjected to torture techniques, including water-boarding.
According to diplomatic cables published by Wikileaks in the Irish Independent in 2010, former Foreign Affairs Minister Dermot Ahern told the US ambassador Thomas Foley he was "quite convinced" that at least three flights involving renditions had refuelled at Shannon Airport.
In response to the latest figures of the US army's use of Shannon, current Foreign Affairs Minister Charles Flanagan said permission for the landing of foreign military aircraft at Shannon airport is only granted on the condition that the aircraft are unarmed, carry no arms, ammunition or explosives, do not engage in intelligence gathering, and that the flights in question do not form any part of military exercises or operations.
Margaretta D'Arcy, an 80-year-old artist and anti-war activist was released early from prison last month after serving part of a second prison sentence over her opposition to the US military use of Shannon Airport. D'Arcy is a close friend of President Michael D Higgins and his wife Sabina.
Over the past decade, Shannon has been frequently used as a stopover by American C-130 Hercules military transport aircraft, with as many as four landing in one 48-hour period in November 2010. These heavy cargo aircraft are used to carry troops as well as heavy munitions and other goods. Other US Air Force and Navy aircraft recorded at Shannon included C-17 Globemaster turbofan aircraft, capable of airlifting large payloads over intercontinental ranges without refuelling, and C-9 Skytrain military passenger aircraft.
The US also uses specially adapted passenger aircraft to transport its troops through Shannon.