His administration say it will be used to protect against Iran and North Korea
Donald Trump has announced plans to develop a missile defence system to protect the US against attacks from Iran and North Korea.
Within minutes of his inauguration as US president, Mr Trump's administration said it would develop a "state-of-the-art" system.
It did not provide details on whether the missile defence system would differ from those already under development, how much it would cost or how it would be paid for.
In a military policy statement on the White House website, the Trump administration says the move was part of its strategy to "rebuild our military".
It says: "President Trump will end the defense sequester and submit a new budget to Congress outlining a plan to rebuild our military.
"We will provide our military leaders with the means to plan for our future defense needs.
"We will also develop a state-of-the-art missile defense system to protect against missile-based attacks from states like Iran and North Korea.
"Cyberwarfare is an emerging battlefield, and we must take every measure to safeguard our national security secrets and systems.
"We will make it a priority to develop defensive and offensive cyber capabilities at our US Cyber Command, and recruit the best and brightest Americans to serve in this crucial area," it adds.
While a separate foreign policy statement, entitled "America First Foreign Policy", states: "Defeating ISIS and other radical Islamic terror groups will be our highest priority.
"To defeat and destroy these groups, we will pursue aggressive joint and coalition military operations when necessary.
"In addition, the Trump Administration will work with international partners to cut off funding for terrorist groups, to expand intelligence sharing, and to engage in cyberwarfare to disrupt and disable propaganda and recruiting."
"Finally, in pursuing a foreign policy based on American interests, we will embrace diplomacy.
"The world must know that we do not go abroad in search of enemies, that we are always happy when old enemies become friends, and when old friends become allies.
"The world will be more peaceful and more prosperous with a stronger and more respected America", it adds.
Additional reporting: IRN