Northern Ireland First Minister Peter Robinson and his deputy Martin McGuinness have begun a trade mission to the US.

Both men will use a series of engagements in Los Angeles, San Francisco, Chicago and Washington to drum up inward investment and enhance political links in the build-up to St Patrick's Day.

The heads of the Stormont Executive began their trip as data published by Ulster Bank pointed to "a further sharp rise in business activity".

The bank’s latest monthly survey of economic activity concluded that “rates of growth remain very strong”, but found that the rate of growth had eased slightly since January.

It also found the retail and construction sectors were performing particularly well.

"The Northern Ireland Executive has put the development of the economy at the heart of our Programme for Government," said Mr Robinson. "Engaging with the United States is a vital element of the economic and political development of Northern Ireland."

He added: “The United States is the number one source of foreign direct investment into Northern Ireland, with165 US-owned businesses and over 18,000 employees. The United States is also significant to our export market, which in 2012/13 exported £534 million [€640 million] to the United States.

“I look forward to a very informative and productive visit and I will be availing of every opportunity to attract further investment and increase tourism to Northern Ireland.”

The First Minister added: “There is a strong bond between the US and the North of Ireland.

“Over the last five years, US-owned companies generated over 4,300 jobs, resulting in £137 million of salaries, and investment in research & development of £100 million.

“Foreign direct investment brings many benefits, creating new jobs and helping to boost economic growth. It also generates additional opportunities within the local supply chain and leads to the expansion and growth of many home-grown businesses.

“International relationships are developed through face-to-face meetings and this week offers another opportunity to strengthen relations with the US and pursue opportunities to grow our economy.”

Addressing the latest data from Ulster Bank, Richard Ramsey, the bank's chief economist, said: "Northern Ireland's broad-based economic recovery continued last month, with all sectors posting further growth in business activity, employment and new orders.

“The UK and the Republic of Ireland, Northern Ireland’s two key trading partners, also saw an easing in the pace of growth in business activity and new orders in their February PMI surveys, whilst local firms reported an easing in the pace of job creation in February, down from January’s six-and-a-half-year high.”