US President Donald Trump has expressed optimism about ending the war in Afghanistan while simultaneously threatening the United States could “wipe (it) off the face of the earth” within “10 days”.

During a White House meeting with Pakistani Prime Minister Imran Khan on Monday (US time), Mr Trump talked up a deal that could maintain pressure on the Taliban and end the near 18-year-old war in Afghanistan.

“I could win that war in a week… it would be over in literally 10 days,” Mr Trump told Mr Khan at the meeting.

“I don’t want to kill 10 million people … Afghanistan could be wipe[d] off the face of the earth. I don’t want to go that route … I have a plan that could win that war in a very short period of time.”

do you think the president understands that we're not actually at war *with* afghanistan https://t.co/FcEArdp9Mt

— Christopher Hooks (@cd_hooks) July 22, 2019

Tensions among Islamic republics and the US remain high in the Middle East, with Iranian authorities confirming on Monday they had arrested 17 suspected US spies.

All of the alleged spies, believed to be CIA operatives, were Iranian nationals.

Those who refuse to cooperate with Iranian authorities face execution or a long prison sentence.

At the same White House meeting with Mr Khan, Mr Trump also offered to resolve India and Pakistan’s long-standing territorial dispute over Kashmir. He claimed the Indian government had invited him to help it come to a deal.

New Delhi promptly denied the invitation, saying “no such request” had been made by Indian President Narendra Modi.

Mr Trump also floated the possibility of restoring the $US1.3 billion in aid he cut from Pakistan last year.

The US and Pakistan have a complicated relationship.

Mr Trump last year complained on Twitter that the Pakistanis “have given us nothing but lies & deceit” and “give safe haven” to militants.

“They were really, I think, subversive. They were going against us,” Mr Trump said on Monday, adding that the US relationship with Pakistan had improved.

Mr Khan told Mr Trump that a peace deal with the Taliban was closer than it had ever been.

“We hope that in the coming days we will be able to urge the Taliban to speak to the Afghan government and come to a settlement, a political solution,” Mr Khan said in the Oval Office meeting.

Mr Trump wants to wrap up US military involvement in Afghanistan and sees Pakistan’s co-operation as crucial to any deal to end the war and ensure the country does not become a base for militant groups like Islamic State.

Washington wants Islamabad to pressure Afghanistan’s Taliban into a permanent ceasefire and participation in talks with the Afghan government.

Mr Trump last year slashed millions of dollars of security assistance to Islamabad. Pakistan has denied the accusations.

The Pentagon said Pakistan’s army chief, General Qamar Javed Bajwa, will meet the top American military officer, chairman of the US Joint Chiefs of Staff General Joseph Dunford, later on Monday.

Analysts believe General Bajwa will play a key role in behind-the-scenes discussions, with the military looking to persuade Washington to restore aid and co-operation.

-with AAP