Seeking India's [Images] support against Iran's controversial nuclear programme, US President George W Bush [Images] has said it was important to send a "firm message" to Tehran that "development" of a nuclear weapon by it is "unacceptable."

"What's important is that India, Pakistan, and the United States work together to send a firm message to the Iranians that a development of a nuclear weapon is unacceptable," he told Pakistani reporters here when asked about the proposed pipeline project between India, Iran and Pakistan.

We have an ambitious agenda with India

He said he "fully" understood that energy supplies were important for India as well for Pakistan. "But a country which has been unwilling to adhere to treaties that it's agreed to, a country the President of which has said the destruction of Israel is -- part of foreign policy, a country which has not told the truth when it comes to whether or not they're enriching uranium, is a country that free nations need to deal with in a diplomatic way. And the best thing that the Iranians can hear is a unified message from all of us," he said.

Asked if at some particular date he will decide to take military action against Iran, Bush replied: "Diplomacy is our first option."

Complete coverage: The Indo-US nuclear tango