Mrs Clinton said after talks with Prime Minister Yingluck Shinawatra yesterday evening during her visit to Thailand that the amount was in addition to the $1.1 million in direct humanitarian aid previously given via the Thai Red Cross, the US Agency for International Development (USAID), and the International Organisation of Migration (IOM).

Diplomatic sources said the new pledge included US$750,000 to be allocated via USAID, money to drain the water from and repair Don Mueang airport, rebuild 10 police stations, and restore the ancient and World Heritage sites in Ayutthaya.

Ms Yingluck said she had discussed with Mrs Clinton the possibility of using U-tapao airport in Sattahip for humanitarian assistance for disaster relief.

The two sides also discussed damage to crop cultivation as this posed great concerns about food security.

Ms Yingluck reaffirmed to Mrs Clinton her government's goals for political reconciliation and the ongoing work of the Truth and Reconciliation Commission.

Mrs Clinton said the US had worked closely with the government from the start of the floods to find ways to help in disaster relief and recovery.

"Support for the Thai economic recovery is also included. This flood has posed early challenges to the Thai government and to the hard-won peace achieved after the political violence you have endured through recent years," said Mrs Clinton.

She said the US stood behind Thailand to consolidate strong institutions, good governance, guaranteeing the rule of law and protecting human rights and fundamental freedoms.

When asked about the amnesty discussion, Mrs Clinton said she had encouraged the government to move forward in the reconciliation process to address the violence surrounding the political unrest in recent years.

Mrs Clinton also offered her sympathies to the Thai people saying that among natural disasters of all kinds, flooding was probably the worst. "It's hardest to begin rehabilitation as we don't know when the water will rise and recede. We have great sympathy.

"In restoration and recovery, you will come back even stronger, and we expect even more from Thailand in the future," she said.

Earlier, United Nations Secretary-General Ban Ki-moon called on international leaders to show their political will by committing to climate change initiatives at an upcoming conference in South Africa in light of the disastrous flooding in Thailand.

Addressing a joint press conference with Ms Yingluck during his one-day visit to Bangkok yesterday, Mr Ban said countries needed to tackle the climate change problem urgently.

"I am urging the leaders to address these matters with a sense of urgency," he said. "We do not have any time to waste."

He reaffirmed the UN's support for Thailand in its efforts to recover from the flood disaster.