President Michael D Higgins today led congratulations to Barack Obama on his re-election to the White House.
Mr Higgins offered his US counterpart “the continued goodwill and best wishes of the people of Ireland.”
Mr Obama, who visited Dublin and his ancestral home in Moneygall, Co Offaly last year, defeated Republican challenger Mitt Romney.
In a letter to Mr Obama, President Higgins said: "The international community faces many daunting challenges and we look forward to your continued leadership and constructive engagement in the period ahead.
"The very close and warm relationship between Ireland and the United States has, with your help and encouragement, prospered during your tenure," he said. "I am confident that, under your leadership, our bilateral relations will be further advanced during the next four years."
Taoiseach Enda Kenny said he has written to Mr Obama and vice-president Joe Biden "congratulating them on their great victory".
He said Ireland and the US "enjoy an especially warm and friendly" relationship. "This has been strongly reflected during President Obama's first term of office, never more so than during his wonderful visit to Ireland last year," he said.
"I am confident that the relationship between our two countries will continue to flourish during his coming term of office, as our administrations continue to work together across a range of policy areas in our respective efforts to boost our economies, increase trade and investment, and create new and sustainable jobs."
Mr Kenny said he looks forward to working closely with Mr Obama and the United States as Ireland assumes the presidency of the European Union on January 1st.
Tánaiste Eamon Gilmore also congratulated the US president and said he looked forward to working with his administration. “We have work of course to do, we have work to do across a number of areas and next year when Ireland holds the presidency of the European union we will be working on a European Union-US trade agreement to try and grow both of our economies," he said at a US embassy election event in Dublin.
Elsewhere, British prime minister David Cameron said he has "really enjoyed" working with Mr Obama "over the last few years and I look forward to working with him again over the next four years".
Fianna Fáil Leader Micheál Martin said he hoped the president will return to Ireland during his second term. He added that by "working together to foster strong ties and increased trade and economic links both Europe and America have strong, bright futures ahead."
Sinn Féin deputy leader Mary Lou McDonald congratulated Mr Obama in the Dáil, while the North's First Minister Peter Robinson and Deputy First Minister Martin McGuinness said in a joint statement: "The American administration has always been a strong supporter of the peace and political process and we do not underestimate the positive role it has played over recent years."
"We wish President Obama and the First Lady every success as he begins his second term of office."
Elsewhere, British prime minister David Cameron said he has really enjoyed working with Mr Obama "over the last few years and I look forward to working with him again over the next four years".
Speaking from Jordan, Mr Cameron said he wanted to see an EU-US trade deal and action on Syria.
"Right here in Jordan I am hearing appalling stories about what has happened inside Syria so one of the first things I want to talk to Barack about is how we must do more to try and solve this crisis," he said.
"Above all, congratulations to Barack. I've enjoyed working with him, I think he's a very successful US president and I look forward to working with him in the future."
British Labour leader Ed Miliband tweeted: "Congratulations to @BarackObama - great victory based on building fairer economy and optimism about what politics can achieve."
Middle East envoy Tony Blair said Mr Obama's election victory opened the way for renewed efforts to revive moribund peace negotiations between Israel and the Palestinians.
Russian president Vladimir Putin said he hoped Obama's re-election will have a positive impact on ties with the US.
Foreign minister Sergei Lavrov also said Moscow was ready to take cooperation with the US government as far as Washington was willing to go.
Indian prime minister Manmohan Singh, paid tribute to Mr Obama in a letter, saying "your mandate gives you a historic opportunity to continue to work for the welfare of the American people as also for global peace and progress at an admittedly difficult juncture, not just for the US, but indeed for the world at large."
Simon Schama, a professor at Columbia University in the US, said Mr Obama has done “not a bad job at all” in the face of the “horrendous poison chalice” he was given four years ago in terms of the economic difficulties facing the country.
“Barack Obama in the second term has nothing to lose, it is not the case I think as people kept on saying earlier on in the evening that he is going to be faced with an even more brutally ferocious House, he will, but it means something to have been re-elected.”
Additional reporting: PA
