President Donald Trump on Thursday called on Iran to pursue a "meaningful” agreement as the U.S. continues reinforcing its military posture in the Middle East amid rising tensions.

"It's proven to be over the years not easy to make a meaningful deal with Iran. We have to make a meaningful deal otherwise bad things happen," Trump told the inaugural meeting of the "Board of Peace," his initiative to secure stability in Gaza.

He warned that Washington "may have to take it a step further" without any agreement, adding: "You're going to be finding out over the next probably 10 days."

Trump announced that nine members of the body have agreed to pledge $7 billion toward a Gaza relief package.

Kazakhstan, Azerbaijan, UAE, Morocco, Bahrain, Qatar, Saudi Arabia, Uzbekistan and Kuwait are the countries that are making pledges, Trump added.

"But every dollar spent is an investment in stability and the hope of new and harmonious (region)," said Trump in thanking the donors.

The amount, while significant, represents a fraction of the estimated $70 billion needed to rebuild the Palestinian territory decimated after two years of war.

Trump also announced the U.S. was pledging $10 billion for the Board of Peace, but didn't specify what the money will be used for.

"The Board of Peace is showing how a better future can be built, starting right here in this room," Trump said.