Lindsey Hilsum worries about China

China's economic interests are blooming into military ties: arming militaries in Latin America, for

Jack cosied up to Condoleezza, but maybe Margaret needs to become Li's best friend. Or even Sergei's. The Chinese foreign minister Li Zhaoxing and Russia's Sergei Lavrov may not be as glamorous as the US secretary of state, but increasingly they hold the diplomatic levers influencing world events.

At Mrs Beckett's first high-level international meeting, held in New York on 8 May, Sergei and Li put a spanner in Condoleezza's works (so to speak). They refused to agree a UN Security Council resolution making it illegal for Iran to enrich uranium. Neither Russia nor China wants Iran to build a bomb, but they don't want sanctions against the Islamic Republic of Iran, either. They feared that the resolution, in its current form, would be the first step.

Cast your mind back to 1991 and the first Gulf war. A weakened Russia went along with the American plan to dislodge Saddam Hussein from Kuwait. China scarcely figured. Both countries' protestations over Kosovo in 1999 were a nuisance to Europe and the US but not an obstacle. Their objections over Iraq in 2003 were dismissed. But now the world is different. America has shot its bolt in Iraq - for every hawkish voice threatening military force against Iran, there are dozens in Washington saying diplomacy is the only way, and that means re-engaging China and Russia as well as Europe.

With oil at more than $72 a barrel, Russia has become rich. During last winter, the Russians made sure everyone knew they are powerful, too. They cut gas supplies to Ukraine and threatened western Europe with an energy shortage. The Americans are worried - recently Dick Cheney tried to cut Russia down to size, accusing it of holding back democracy and using its reserves of oil and gas as "tools of intimidation or blackmail". President Putin seems unfazed, because oil money bolsters his increasingly authoritarian government, which scarcely tolerates human-rights campaigners or reporters investigating corruption and the abuse of state power.

Paradoxically, China's strength comes partly from its thirst for oil. As the second-largest energy consumer in the world after the US, it is combing the globe for new sources of oil and gas. No wonder the Chinese don't want sanctions imposed on Iran - they've signed a deal to develop Iran's largest natural gas field, and a long-term contract for both oil and gas.

Just as western powers begin to exert a little more pressure on the Sudanese government to end killings in Darfur, Beijing has drawn even closer to Khartoum. In early April, Sudan opened a new oil pipeline, increasing output from 300,000 to 500,000 barrels per day. The oil goes straight into tankers bound for China. The majority of shares in the pipeline company are owned by two state-owned Chinese oil companies. A few days after the pipeline inauguration ceremony, China abstained from a UN Security Council resolution imposing a travel ban and asset freeze on four prominent Sudanese accused of committing atrocities in Darfur. If the resolution had included all those initially slated for sanctions, the Chinese would have exercised their veto. Europe and the US may have done little to stop the massacres in Darfur, but China has built three arms factories in Khartoum and backed the Sudanese government.

Now the US is worried about Chinese influence in Latin America. China is the fourth-largest trading partner for Argentina and Brazil, signing $20bn in commercial agreements and investing $7bn in ports and railways. Swathes of pampas and rainforest are being cut down to make way for soybeans to be exported to China.

Economic interests are blossoming into diplomatic and military ties. In March, General Bantz J Craddock, who heads the US Southern Command, told a Senate committee that China was beginning to arm and train Latin American militaries. "If we're not there and can't provide this opportunity, someone else will," he said. In 2002, the US passed a law withdrawing military co-operation from countries that refused to provide immunity to US service personnel facing prosecution by the new International Criminal Court. The aim was to weaken the court, penalising countries that dared to defy the US. But 12 Latin American countries - including Mexico, Brazil and Venezuela - refused to sign. China, according to General Craddock is "offering resources to cash-strapped militaries and security forces with no strings attached".

The European left will delight in these blows to US hegemony, but Latin American activists say China's hunger for resources is denuding the rainforest, drying up the Amazon and polluting the atmosphere. Anti-corruption and human-rights campaigners in Africa say their governments can act with impunity because Chinese investment comes with no conditions. In Russia, journalists and non-governmental activists are finding it harder to operate as the state curtails what it sees as anti-government activities.

The past decade has shown the dangers of the unipolar world, but the rise of Russian and - more significantly - Chinese power is not, in itself, without peril.

Lindsey Hilsum has just been appointed as the first Channel 4 News Beijing correspondent