US officials at the National Oceanic and Atmospheric Administration said although American lobsters have been found off the Swedish coast, their small numbers could not develop into a threat against the local population.
"There just isn't enough scientific information that gives you the impression that this is something that could take hold, which is important in the invasive-species standard internationally," Steven Wilson, a deputy director of the administration, known as NOAA, said during a telephone news conference.
The American lobster, also known as the Canadian lobster, lives off the north-eastern coast of North American. It was first found in Swedish waters in 2008 and since then there have been more than 30 caught alive along Sweden's west coast.
Sofia Brockmark, senior adviser at the Swedish Agency for Marine and Water Management, said the agency is looking into NOAA's review and would prepare a response.
She said although the American lobster is not an established invasive species in Sweden right now, the agency believes it has a potential to become one.
"We know from other species that it takes a relatively long time before it happens but when it happens there is nothing you can do to prevent that," she told Radio Sweden.
Back in March, Sweden formally requested that the American lobster be added to the EU's list of invasive species. Doing so would ban importing, selling and raising the creature throughout the union's 28 member states.
It's currently illegal to release American lobsters into Swedish waters but the crustacean can be bought live in Sweden. According to the Sweden Agency for Marine and Water Management, more than 13,000 tons of live American lobsters are imported to Europe annually.
Swedish researchers believe the larger American lobsters could out-compete native species for shelters and food. They also said American lobsters could spread diseases or parasites.
Although the lobster has been found off the coast of Norway and Great Britain, Sweden is the only country so far to call for an outright ban.