US President Donald Trump's first budget shows big jump for defence spending and steep reductions for aid and health.

US President Donald Trump's first budget shows large increases in defence and military spending, expanding the budgets for both the Pentagon and the Department of Homeland Security.

In a plan designed to translate campaign promises into dollar and cent commitments, about $4bn will be earmarked this year and next to start building a wall on the US southern border.

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Meanwhile, the Department of State and environmental agencies will have to make do with smaller budgets.

The budget may be seen as a signal to the world that Trump's US may be less engaged and will put "America first".

READ MORE: Trump 'seeks $54bn increase' in military budget

The Environmental Protection Agency, which helps monitor air, water and other standards, will also see significant cuts.

In a recent speech in Detroit, Trump also announced he would freeze targets to limit future vehicle emissions. That is in keeping with Trump's promise to gut regulation.