US officials have demanded access to an American citizen who has been detained in Russia on suspicion of being a spy, saying it expected the Kremlin to abide by its obligations under the Vienna convention.

The statement by the state department came hours after Russia’s domestic security service said an American had been arrested on Friday “while carrying out an act of espionage”.

The FSB, the successor to the Soviet-era KGB, said in a statement, published in Russian, that a criminal case had been opened “under article 276 of the criminal code (espionage)”. The name of the detained American appeared to translate as Paul Whelan, but no details, including evidence of the nature of the alleged spying, were given.

Citing confidentiality concerns, the US government declined to confirm the name of the detained American.

The development could have serious diplomatic repercussions at an already fraught time for Russia-US relations. People convicted of spying in Russia face a prison term of between 10 and 20 years.

A state department spokesperson on Monday said it had been made aware of the detention by Russia’s ministry of foreign affairs. The spokesperson also suggested but did not confirm that the US had not yet had any access to the individual.

The state department said Russia had an obligation under the Vienna convention to give US consular access to the individual. “We have requested this access and expect Russian authorities to provide it.”

The arrest comes as prosecutors in the US are investigating Russia’s attempts to sway the 2016 presidential election in favour of Donald Trump.

While it is far from clear whether the Russian arrest was related to the US investigation, Moscow’s move followed the guilty plea in December of a 30-year-old Russian woman who was living in the US and admitted to secretly acting as an agent of Moscow. Maria Butina – who pleaded guilty after a period in solitary confinement in a US prison – had extensive contact with senior Republican operatives and politicians and sought to infiltrate the National Rifle Association. She also gave information about US politicians to a Russian government official.

Vladimir Putin has said that “nobody” in Russia’s spy agencies knew Butina. But her arrest and the handling of her case marked a sore point in the US and Russian relationship. Before her guilty plea to being a foreign agent, Butina was reportedly visited in prison at least six times by the Russian consulate and was twice a subject of discussion between Mike Pompeo, the US secretary of state, and his counterpart, Sergey Lavrov. The hashtag #FreeMariaButina was also used by the Kremlin’s official Twitter account, and the Russian-backed news outlet RT published several articles about her.

The arrest of the American in Russia was announced shortly after Putin expressed a desire for better relations in 2019 with the US, after a year in which diplomacy between the west and Russia was at its frostiest since the cold war.

Britain expelled 23 Russian diplomats over accusations that the Kremlin was behind the novichok attack in March on the former double agent Sergei Skripal and his daughter, Yulia, in Salisbury, Wiltshire. Russia denied any involvement in the poisoning and, in retaliation, sent home the same number of British embassy workers.

In October, the US justice department accused seven Russians of being GRU military intelligence officers, charging them with hacking and wire fraud. Four men from that group were expelled from the Netherlands in April after being caught allegedly attempting to hack into the Organisation for the Prohibition of Chemical Weapons.

But in his new year letter to Trump, Putin said Moscow was ready for dialogue on a “wide-ranging agenda”. A Kremlin statement said Putin’s letter stressed that Russia-US relations were “the most important factor for providing strategic stability and international security”.

There are small signs of improved relations between Russia and the UK: Russia’s embassy in London said on Friday that Moscow and London had agreed to return some staff to the respective embassies.

The US embassy in Moscow could not immediately be reached for comment on Monday, a public holiday in Russia.