Anti-war activists are protesting outside Shannon Airport ahead of a brief stopover by US President George W Bush early tomorrow morning.
Airforce One is stopping to refuel on its return flight to the US from south Asia.
Gardaí say the flight is expected to land at around 3am.
More that 500 gardaí and defence force personnel are providing a major security cordon at the airport, where at present only a handful of people are protesting.
Mr Bush's aircraft will stop at Shannon while en route to the US from his visits to India, Afghanistan and Pakistan.
Earlier today, Mr Bush held talks in the Pakistani capital, Islamabad, with President Pervez Musharraf on the last stage of his tour of Asian countries.
At a news conference, Mr Bush said a lot of work remained to be done to defeat the al-Qaeda network.
He also reaffirmed the strategic partnership between Pakistan and the United States and said Mr Musharraf remained committed to the fight against extremism.
Yesterday, Mr Bush ended his visit to India with a speech highlighting the partnership between the two countries.