VATICAN CITY - Pope Benedict XVI moved swiftly on the first day of his reign on Wednesday to allay fears of a rigid, authoritarian papacy, saying he would work for dialogue both within the Church and with other faiths.

In his first public Mass since his election, German Joseph Ratzinger, 78, made an early effort to soften his image and deflect concerns aroused by his past as a tough doctrinal enforcer who harshly dismissed other Christian denominations.

The new Pope said he felt "inadequacy and human turmoil" at his election, a choice that was welcomed by conservatives but caused consternation among Church reformers.

"I welcome everybody with simplicity and love to assure them that the Church wants to continue in open and sincere dialogue with them, in search of the true good of man and society," he said at the Mass with the red-hatted cardinals who elected him.

Sitting in front of Michelangelo's fresco of the Last Judgment in the Sistine Chapel where he was elected, and dressed in white and gold vestments, the pontiff said he felt his predecessor, John Paul, was guiding him and holding his hand.

"I will spare no effort and commitment to continue the promising dialogue with other civilisations that was started by my venerable predecessors," Benedict said. Jewish and Muslim leaders have already called for contacts to continue.

The election, in one of the swiftest conclaves for a century, was widely seen as reflecting the cardinals' determination for continuity with John Paul's stern rule. "A Warrior to Challenge Modernity," said Italy's La Repubblica daily newspaper on its front page.

The strict defender of Catholic orthodoxy for 23 years, Ratzinger made clear in recent speeches that he would brook no dissent and would block debate on issues such as women priests, priestly celibacy, abortion and homosexuality.

Much global newspaper coverage was negative. "He is dry and hard, as the infinite number of Catholic clergymen and theologians persecuted mercilessly by the German cardinal know well," said the Mexican leftist daily La Jornada.

Concern in Turkey

Newspapers in Turkey expressed concern that the new Pope's past opposition to Ankara joining the European Union because it is a Muslim nation could raise fresh obstacles to membership.

The election of one of John Paul's closest aides was greeted by a shower of congratulations from world leaders and delight from conservatives, but with deep disappointment among those who hoped for reform in the Catholic Church.

South African Anglican Archbishop Desmond Tutu called Benedict a "rigid conservative" out of step with the times.

"We would have hoped for someone more open to the more recent developments in the world, the whole question of the ministry of women and a more reasonable position with regards to condoms and HIV/AIDS," Tutu said.

There was also negative reaction from Protestants still smarting from a document written by Ratzinger in 2000 that dismissed their denominations as "not proper churches."

But Israelis and Jewish groups praised Benedict, saying he had atoned for his wartime membership -- that he says was enforced -- in Nazi Germany's Hitler Youth by playing a key role in John Paul's efforts toward Jewish-Catholic reconciliation.

Italian newspapers said the rapid conclusion of the conclave after only four votes suggested Ratzinger had exploited the momentum of his front-runner status before a more moderate wing could unite around one candidate.

The clear favorite before the conclave, he also confounded the Roman maxim: "He who enters as Pope leaves as a cardinal."

Friends and colleagues said the world had yet to see the warmer side of a man who has been dubbed in the Italian press as the "panzer cardinal" and "God's Rottweiler." "You will see that his personality will surprise many, a great many people. It will surprise them because of this slightly caricature-like image that people have of the cardinal he was," said Spanish Cardinal Carlos Amigo Vallejo.

The new Pontiff made his first appearance outside the Vatican City state on Wednesday, briefly returning by limousine to his nearby apartment in Rome. Wearing a white skull cap and papal cassock he smiled at cheering crowds gathered outside.

"I am truly moved," he told Reuters as he left to return to the Vatican, when asked how he felt about his election.

Oldest Pope for Three Centuries

The Church's 265th pontiff, Benedict is the oldest man elected pope for 300 years and the first German for a thousand.

In his native Germany, the news aroused competing emotions from pride to doubts and outright dismay in a nation that sees itself as secular, liberal and progressive.

"In my opinion the man is simply too old for this office," said Agnes Straubinger, a resident of Munich in Ratzinger's native Bavaria. "How will the Catholic Church ever progress if it always bases itself in the past?"

President Bush joined other foreign leaders in heaping praise on Benedict, a respected theologian of steely intellect, hailing him as "a man of great wisdom and knowledge."

But the shy prelate, while sharing the strict orthodoxy of John Paul, will mark a sharp change of style from his charismatic predecessor, who was the world's most-traveled pontiff and was 20 years younger than Ratzinger when he ascended the papal throne.

The cardinals were believed to have chosen an elderly man as a transitional pope after the 26-year reign of John Paul, the third-longest in Church history.

There was a festive atmosphere in St. Peter's Square where a few thousand excited tourists milled around.

Souvenir sellers were doing a brisk trade in photographs of the new Pope and said more memorabilia were on the way.