Traffic restrictions are in place in Dublin city centre ahead of the visit of US President Barack Obama on Monday.
Mr Obama is due to address crowds after a free concert on College Green.
Gardaí sealed off access to Dame Street at 6am and the street will remain closed until next Tuesday.
Dublin Bus has warned that a number of routes will be affected by the restrictions in the city centre from today.
Gardaí say the Phoenix Park will also be closed to everyone, with the exception of visitors to Dublin Zoo today and tomorrow, although the Zoo will be closed on Monday.
Iarnroód Éireann has also warned of some delays and disruption to services on Monday.
The Irish Aviation Authority has said that arrivals and departures from Dublin Airport will be suspended for up to 30 minutes during his arrival on Monday morning. The same will happen during his departure on Tuesday.
Mr Obama will travel to Áras an Uachtaráin to meet President Mary McAleese before a meeting with Taoiseach Enda Kenny at Farmleigh.
He is then expected to fly by helicopter to his ancestral home in Moneygall, Co Offaly, wheretraffic restrictions will also be in place.
That evening, Mr Obama will address the public after a concert on College Green on Dame Street.
The Waterboys, Westlife, Imelda May and Jedward are among the acts that will perform.
It is understood that Mr Obama will stay overnight in the US Ambassador's residence in the Phoenix Park.
On Tuesday morning, he travels to London to address parliament.
He then heads to France for a G8 summit and concludes his European visit in Poland.
The existing parking restrictions will continue until Tuesday on Chesterfield Avenue, north and south quays, Parkgate Street, D'Olier Street, Westmoreland Street, College Street, and Grafton Street.
Parking will also be restricted on Nassau Street, South Leinster Street, Lincoln Place, Westland Row, Pearse Street, Christchurch Place, Lord Edward Street, Merrion Square, Merrion Street and Fitzwilliam Place.
There will also be parking restrictions from today on Mount Street, Northumberland Road, Baggott Street, Pembroke Road, Raglan Road, Clyde Road and Herbert Park.