The leaders of Armenia and Azerbaijan plan to sign a joint declaration at the White House on Friday — committing to a peace deal facilitated by the Trump administration that would end nearly four decades of conflict between the two countries.

Both nations are also expected to sign agreements expanding bilateral ties with Washington, a breakthrough made possible because the U.S. helped resolve a dispute over the development of a shared transit corridor, according to three U.S. officials.

“I look forward to hosting the President of Azerbaijan, Ilham Aliyev, and the Prime Minister of Armenia, Nikol Pashinyan, at the White House tomorrow for a Historic Peace Summit,” Trump posted Thursday on his Truth Social platform. “The United States will also sign Bilateral Agreements with both Countries to pursue Economic opportunities together, so we can fully unlock the potential of the South Caucasus Region.”

Key to easing the long-standing conflict is the agreement on the transit corridor, which includes a commitment to developing the mountainous stretch of Armenian territory between Azerbaijan and its Nakhichevan exclave known as the Zangezur Corridor, said the three officials, who were granted anonymity to preview the White House ceremony.

“We were able to boil it down to ‘if we can just unblock one of the pieces, maybe the rest of the pieces begin to fall into place,’” one of the officials said.

In a Trumpian flourish, the U.S. has deemed the corridor the Trump Route for International Peace and Prosperity and is calling Friday’s event the TRIPP Peace Summit.

Armenia has agreed to award the U.S. exclusive special development rights on the Zangezur Corridor land for 99 years. The U.S. would sublease the land to a consortium that will develop rail, oil, gas and fiber optic lines and possibly electricity transmission along the 27-mile corridor.

The joint declaration is believed to be the first ever bilateral declaration signed by the two long-hostile countries, said the third official. The foreign ministers are expected to initial the text of a treaty that the sides said they had agreed to in March but have made slow progress on since.

“Tomorrow is the handshake in writing the check, and we still have to ink the contract and cash the check,” the official said.

The agreement is the culmination of decades of U.S. efforts to broker an end to the conflict, which arose when the countries gained independence from the Soviet Union. The Biden administration came close to securing a similar deal.

As part of the agreement, the U.S. will make several gestures of goodwill towards Baku, a once-close ally that has gravitated toward Russia in recent years.

The U.S. will lift restrictions on defense cooperation with Baku when the administration issues a document waiving a section of the Freedom Support Act of 1992, a law that prohibits direct assistance to the government of Azerbaijan because of its disputes with Armenia.

Administrations have allowed such aid after the Sept. 11, 2001, terrorist attacks under a waiver authority. But the Biden administration quietly paused it as Aliyev kept floating the idea of future military operations against Armenia. At one point, Baku received $100 million worth of military equipment and other funding from the U.S.

Under the agreement, Azerbaijan and Armenia will also leave the OSCE Minsk Group — which also includes France, Russia and the United States — and worked for decades to try and resolve the dispute between the two countries. Azerbaijan had protested since the outbreak of a 2020 war between the two countries that the OSCE Minsk Group was no longer needed since Azerbaijan had taken the disputed Nagorno-Karabakh enclave by force.

The agreement is expected to disappoint many Armenian-Americans because it apparently lacks specific provisions to address the displacement of people from the historically Armenian enclave as well as prisoners of war taken in the conflict.

“Real peace must be predicated on justice and accountability for Azerbaijan’s ongoing human rights violations — these issues shouldn’t be left on the back burner,” said Alex Galitsky, program director at the Armenian National Committee of America advocacy group. “A deal that rewards Azerbaijan’s aggression, undermines Armenia’s sovereignty, and denies justice to Artsakh’s Armenians will only make it harder to resolve these critical human rights issues down the line.”