The Washington Seven yesterday opened the Smithsonian festival amid criticism from Alliance leader, David Ford, that the number of ministers attending was unnecessary.

However, after addressing hundreds of people in a giant marquee at the launch of the festival, Ministers McGuinness and Robinson said that over 100 Northern Ireland exhibitors at the festival showed its importance to the world.

Minister Robinson agreed that the seven ministers would find it difficult to quantify their achievements at the festival.

"I don't think we can give a list of what we have achieved," he said but added that the festival was a "shop window" to advertise the new Northern Ireland to the world.

Mr McGuinness also defended the trip, saying the 160 Northern Ireland exhibitors showed a united front to the world.

"We are showing a united front and it's not just through our government responsibilities. We are here surrounded by people who are stone masons, artists, mural painters, musicians, poets. They come from our community and they come from every section of our community," he said.

Minister McGuinness said that Northern Ireland could not turn down the opportunity provided by the Folklife festival.

"We are all here together taking advantage of the tremendous, tremendous political breakthroughs in the hope that people will visit and boost our tourist industry," he said.

They were responding to criticism by Mr Ford, who said that only the enterprise and culture ministers should have attended, and only if it helped improve publicity for the Northern Ireland exhibit at the festival.