TEHRAN, Iran —  Iran's hard-line Revolutionary Guards pledged their loyalty Tuesday to the country's ultraconservative president-elect, who called for an end to accusations that he took Americans hostage and killed a Kurdish opposition leader.

The guards' welcome of Mahmoud Ahmadinejad (search) was in stark contrast to their threat four years ago to attack supporters of outgoing reformist President Mohammad Khatami (search) if they threatened Iran's Islamic regime.

The show of support from the nation's most powerful military force came as the president-elect persisted in rejecting claims that he was among radical Iranian students who held 52 Americans hostage for 444 days during the U.S. Embassy takeover in 1979.

Ahmadinejad, who won a landslide victory last month, also denies allegations by Iranian exiles and an Austrian politician of involvement in the 1989 slaying of a Kurdish opposition leader and two associates in Vienna.

"The world has to bow down and respect the will of the Iranian nation," the official Islamic Republic News Agency on Tuesday quoted Ahmadinejad as saying during a meeting with Foreign Ministry officials.

In Vienna, Austria, Greens Party politician Peter Pilz said Tuesday that prosecutors were investigating new information from witnesses for possible links Amadinejad might have to the slaying 16 years ago of Iranian Kurdish politican Abdul-Rahman Ghassemlou (search).

Ghassemlou, the charismatic secretary-general of the Democratic Party of Iranian Kurdistan, had traveled to Vienna for secret talks with envoys from the Tehran regime. Unofficial reports in Iran suggested that Ghassemlou was lured into the meeting to strike a deal on averting conflict with the regime and to discuss hopes for autonomy for his people.

Iran has denounced the claims against Ahmadinejad as part of a smear campaign engineered by the United States and Israel against the new leader.

Brig. Gen. Rahim Safavi, head of the guards, offered more backing to the incoming president, saying his 200,000-member force — which reports directly to Iranian Supreme Leader Ayatollah Ali Khamenei — will serve Ahmadinejad's government.

"It's necessary to declare the readiness of the green-uniform Guards and capable Basijis (hard-line vigilantes) ... to support and cooperate with Your Excellency's serving government," Safavi said in a congratulatory message to Ahmadinejad, state media reported Tuesday.

The vast and well-funded Revolutionary Guards are the most potent force available to the regime, are independent of the regular armed forces and have a broad mandate to confront external and domestic "dangers" confronting the 1979 Islamic Revolution.

In 2000, the guards threatened to strike pro-Khatami reformists with "a hammer on their skull" if they insisted on undermining the country's Islamic ideology. Khatami's well-publicized program of democratic reform sought to protect freedoms and lessen restrictions imposed on Iran by hard-line clerics.