The U.S. must use "smart power" diplomacy and seek global solutions to combat global threats, Hillary Clinton said Tuesday as she appeared before a Senate confirmation hearing to become the next secretary of state.

"America cannot solve the most pressing problems on our own, and the world cannot solve them without America," Clinton told the Senate Foreign Relations Committee.

"The best way to advance America’s interests in reducing global threats and seizing global opportunities is to design and implement global solutions. That isn’t a philosophical point. This is our reality."

Hillary Clinton appears before the Senate Foreign Relations Committee in Washington on Tuesday, her only scheduled appearance in front of the committee. (AP Photo/Susan Walsh)

Clinton, who was Barack Obama's chief rival during the Democratic presidential primaries, appeared to take an indirect swipe at the Bush administration's approach to foreign relations.

"Foreign policy must be based on a marriage of principles and pragmatism, not rigid ideology," she said.

Critics have accused the Bush administration of taking a unilateral and ideological approach to foreign policy.

"I believe that American leadership has been wanting, but is still wanted. We must use what has been called 'smart power,' the full range of tools at our disposal," which include diplomatic, economic, military, political and cultural tools, she said.

"With smart power, diplomacy will be the vanguard of foreign policy," Clinton said.

Clinton said the world faces "great perils" in the form of wars in Iraq and Afghanistan, threats posed by terrorists, the spread of weapons of mass destruction, the dangers of climate change, financial meltdown and worldwide poverty.

She said institutions, including the United Nations, should be used when possible to resolve disputes, but cautioned that military force will "sometimes be necessary, and we will rely on it to protect our people and our interests when and where needed as a last resort."

Few specifics on Iran

Clinton said the greatest threat that the U.S. faces is the danger that weapons of mass destruction will fall into the hands of terrorists.

She added that a strategy of smart power must be employed in Afghanistan, Pakistan and in the Middle East, where it must address "the security needs of Israel and the legitimate political and economic aspirations of the Palestinians."

Clinton said that strategy must also challenge Iran "to end its nuclear weapons program and sponsorship of terror" and persuade both Iran and Syria to "abandon their dangerous behaviour and become constructive regional actors."

But she offered few specifics when pressed by Senator John Kerry, the new chairman of the committee, on what the Obama administration would do in regards to Iran.

Clinton said the administration will pursue a "different approach" and try to engage Iran, adding that no options were off the table. She stressed, however, that Iran acquiring a nuclear weapon was unacceptable.

Asked whether she would engage in personal diplomacy with top Iranian officials, Clinton said she wanted to wait until she was in office and had a chance to consult with others before determining how the administration should proceed.

Ease Cuba restrictions

Clinton also said the administration of the incoming president wants to lift travel restrictions on Americans with family members in Cuba.

"The president-elect is committed to lifting the family travel restrictions and the remittance restrictions. He believes … that Cuban-Americans are the best ambassadors for democracy, freedom and a free-market economy," she said.

Currently, Cuban-Americans are allowed to visit Cuba once every three years and can send as much as $3,000 US annually in quarterly instalments.

Clinton also said she hoped the Cuban government would consider freeing political prisoners and open up the economy.

Darfur, North Korea on agenda

Clinton, wife of former U.S. president Bill Clinton, spoke about a range of global issues, including North Korea's nuclear ambitions, the crisis in Darfur, climate change and the world's economic woes.

Clinton said Obama strongly supports the six-party talks with Pyongyang and views them as an opportunity "for bilateral contact … between North Korea and the United States." South Korea, the U.S., China, Japan and Russia have been negotiating with North Korea in an attempt to get the isolated, impoverished country to abandon its nuclear ambitions.

She criticized Sudan's leadership as a "corrupt and cruel regime" that is compounding a humanitarian crisis. Nearly 300,000 people have died in the country's Darfur region and millions have fled to neighbouring countries in ongoing fighting between government and rebel forces.

"We have spoken about other options, no fly zones, other sanctions and sanctuaries, looking to deploy the UN/AU [African Union] force to try to protect the refugees but also to repel the militias," said Clinton.

She called the world financial crisis the "most severe global economic contraction since the Great Depression" and said it deserves a co-ordinated, diplomatic response.

On climate change, Clinton said Obama believes the U.S. must deliver an urgent response.

"At the extreme, it threatens our very existence, but well before that point, it could very well incite new wars of an old kind, over basic resources like food, water and arable land."

Vote as early as Thursday

Clinton is not expected to face many obstacles at her Senate confirmation hearing.

The committee could vote on her nomination as early as Thursday. Republicans are not expected to block her nomination and it is expected she will be approved.

Although Clinton's confirmation is expected to proceed without a hitch, some questions were raised about her husband's charitable foundation and whether it might pose a conflict of interest for her as secretary of state.

The panel's ranking Republican, Senator Richard Lugar, said that the only way for Clinton to avoid a potential conflict of interest with her husband's charity is to forswear any new foreign contributions. The Indiana senator said the situation poses a "unique complication" that requires "great care and transparency."

"The Clinton Foundation exists as a temptation for any foreign entity or government that believes it could curry favour through a donation," he said. "It also sets up potential perception problems with any action taken by the secretary of state in relation to foreign givers or their countries."

A Jan. 5 letter from Bill Clinton's lawyer stated that ethics officials at the State Department will be allowed to review overseas contributions made to his charity. The State Department will also be allowed to assess in advance the former president's consulting work and speaking engagements.

With files from the Associated Press and Reuters