Prison that symbolises George Bush's 'war on terror' will be shut down, accompanied by ban on torture and review of military trials

Barack Obama has signed an executive order to shut down the US military prison at Guantánamo Bay – the most potent symbol of excess in George Bush's "war on terror".

The new US president signed two other executive orders to review the use of military trials for terror suspects and ban the harshest interrogation techniques, such as waterboarding.

The three executive orders – on the second day of the new administration – showed that Obama was determined to move swiftly to implement some of his key campaign pledges. Administration staff applauded at the signing ceremony in the Oval Office.

"The message that we are sending around the world is that the United States intends to prosecute the ongoing struggle against violence and terrorism and we are going to do so vigilantly," Obama said. "We are going to do so effectively and we are going to do so in a manner that is consistent with our values and our ideals."

A draft copy of the order said: "In view of significant concerns raised by these detentions, both within the United States and internationally, prompt and appropriate disposition of the individuals currently detained at Guantánamo and closure of the facility would further the national security and foreign policy interests of the United States and the interests of justice."

[Read a PDF copy of the order]

An estimated 245 men are being held at Guantánamo, a US naval base in Cuba. Most have been locked up for years without being charged with a crime. Obama's plans to review military trials of terror suspects and end harsh interrogations were being assembled even before he won the election in November.

The UN's torture investigator, Manfred Nowak, welcomed the move and said freed inmates should be allowed to sue the US if they had been mistreated. "Justice also means to look into the past," Nowak told the Associated Press. Nowak has previously said he has reliable accounts of torture at Guantánamo. Lawyers for two inmates, Abd al-Rahim al-Nashiri and Mohammed Jawad, have said their clients were tortured.

In Saudi Arabia, families of the country's 13 remaining Guantánamo detainees rejoiced at the news.

"That was a humane decision. We're very optimistic," said Ali al-Sayari, whose son Abdullah, 28, has been there for eight years. The family has not heard from or about him for the past two years.

"Obama is correcting the mistakes of his predecessor," said Ali al-Shamrani, whose nephew Mohammed al-Shamrani has been in Guantánamo for eight years.

Obama's nominee to be the director of national intelligence is set to tell Congress there will be no torture, harsh interrogations or wiretaps without warrants under his command.

In remarks prepared for his confirmation hearing, retired Admiral Dennis Blair said he believed "torture is not moral, legal or effective".

The signing of the executive orders came as Hillary Clinton, on her first day as secretary of state, pledged to pursue robust diplomacy and effective development to advance America's interests. About 1,000 state department employees gave Clinton a rousing welcome as she spoke at the main entrance to the building. She had been confirmed overwhelmingly in the job by the Senate.

"I will do all that I can working with you to make it abundantly clear that robust diplomacy and effective development are the best long-term tools for securing America's future," Clinton said. "I believe with all my heart that this is a new era for America."

Waiting for Clinton in her office was a letter of welcome and advice from her immediate predecessor, Condoleezza Rice, who was criticised by staff for not doing enough to increase funding for diplomats.

Obama is expected to name George Mitchell, the former Senate Democratic leader, as his Middle East envoy. Mitchell, 75, who helped broker the Good Friday peace accords in Northern Ireland, led an international commission under former president Bill Clinton that investigated the causes of the second intifada in 2000.

In his first full day on the job, the president yesterday telephoned several Middle Eastern leaders including president Hosni Mubarak of Egypt and Ehud Olmert, the Israeli prime minister, in an indication that he will devote serious attention to the Middle East early on in his administration – in sharp contrast to Bush.