Barcelona - Irish supergroup U2 kicked off their world tour in Barcelona with a huge stage show that won gasps of admiration from fans but failed to win over critics, Spanish newspapers reported Wednesday.

90,000 people flocked to Barcelona's Camp Nou football stadium to see the group open their 360 Degrees Tour, which saw singer Bono - almost more famous these days for his campaigning work on Africa than for his music - wrap himself up in both a Irish flag, and a FC Barcelona football shirt.

The band will now got to 14 countries in Europe and North America.

U2 also paid tribute to the late Michael Jackson with their song Angel of Harem.

Featuring a circular stage taking up about half of Europe's biggest football stadium, topped by a metallic spider-like structure known as The Claw, the show included live satellite contact with the International Space Station.

Asked whether they could see Barcelona, the astronauts said they enjoyed the "beautiful sight" of the "blue planet Earth."

Despite the spectacular stage effects, the show was musically "conservative," with a U2 stuck with its "weak recent years" and "predictable" former hits, the daily El Mundo wrote.

It was a "tour for fans" which was unlikely to win the group more followers, the daily concluded.

The daily El Pais described the concert as a "replay of the most popular moments" of one of the world's most successful rock groups. (dpa)