Russian forces have entered an air base in Niger where US troops still remain following the Nigerien junta’s decision to expel them from the country.

US Secretary of Defense Lloyd Austin confirmed that Russian military personnel had entered an air base but were in a separate compound.

He told a news conference in the US that it was not a significant issue as they did not have access to US personnel or equipment.

“Airbase 101 where our forces [are], is a Nigerien air force base that is co-located with an international airport in the capital city. The Russians are in a separate compound and don’t have access to US forces or access to our equipment,” he said.

A senior US defence official had earlier told the Reuters news agency that the situation was “not great but in the short-term manageable”.

US and Russia's military and diplomatic relationships have been frosty since Russia's invasion of Ukraine.

Before the Niger coup last year, the US had been the country's key partner alongside other allies in the fight against Islamist insurgents in the region.

Niger is in Africa's Sahel region, which is considered the new global epicentre of the Islamic State group.

After the coup, Nigerien military leaders have sought closer ties with Russia, after souring relations with Western countries, including France.