MANILA (Reuters) - The Philippines is finalizing a security deal with Russia allowing the two countries’ leaders to exchange visits and observe military drills, a minister said on Monday, at the same time assuring the United States that ties with Moscow will not affect its alliance with its traditional ally.

Philippine President Rodrigo Duterte (4th L) gestures with Russian Ambassador to the Philippines Igor Khovaev (3rd L), Russia's Rear Admiral Eduard Mikhailov (5th L), and other Philippine and Russian officials in front of the Ka-26 anti-submarine helicopter at the anti-submarine navy ship Admiral Tributs at the south pier in Metro Manila, Philippines January 6, 2017. REUTERS/Noel Celis/Pool

Two Russian warships made port calls in Manila last week with President Rodrigo Duterte touring an anti-submarine vessel, saying he hoped Moscow would become his country’s ally and protector.

Duterte has thrown the future of Philippine-U.S. relations into question with angry outbursts against the United States, a former colonial power, and some scaling back of military ties while taking steps to improve relationships with China and Russia.

In October, Duterte told U.S. President Barack Obama to “go to hell” and said the United States had refused to sell some weapons to his country but he did not care because Russia and China were willing suppliers.

He is due to go to Moscow in April. The visit by the Russian warships was the first official navy-to-navy contact between the two countries.

“We will observe their exercises,” Philippine Defence Minister Delfin Lorenzana told reporters during the military’s traditional New Year’s call at the main army base in Manila.

“If we need their expertise, then we will join the exercises. That’s the framework of the memorandum of understanding that is going to be signed. It could be a joint exercises but, initially, its going to be exchange of visits.”

Lorenzana assured Washington the military agreement with Moscow would not allow rotational deployment of Russian troops, planes and ships in Manila for mutual defense.

“It’s not similar to the U.S. which is a treaty, Mutual Defence Treaty, which mandates them to help us in case we’re attacked,” he said. “We wont have that with Russia. The MOU is about exchange of military personnel, visits and observation of exercises.”

He said the Philippines also expected a team of Russian security experts to visit to discuss the sale of new weapons systems.

Last month, Duterte sent his foreign and defense ministers to Moscow to discuss arms deals after a U.S. senator said he would block the sale of 26,000 assault rifles to the Philippines due to concern about a rising death toll in a war on drugs launched by Duterte.