"In response to a threat against the U.S. Embassy, Stockholm, please be advised that the embassy has enhanced its security posture," the statement issued late on Monday read.
The embassy declined to detail the specific nature of the threat in the statement but referred to last week's suicide bombing in central Stockholm.
"In light of last week’s suicide bombing and the increased threat level in Sweden, we think it prudent and necessary to take these additional precautions."
According to embassy spokesperson Chris Dunnet, the threat is however concrete and the measures are not simply a general response to the bombing.
"We have received information that there is a threat against the embassy so we have raised the security level, I can't saying anything more than that," he said.
Dunnet was unwilling to comment further on the origin of the threat and neither on the specific measures taken to tighten security.
"I can't say exactly what we have done to raise the level of security. The Swedish authorities have responsibility for the embassy's security and we have spoken to them and have a good working relationship," he said, while pointing out that a move of this kind is not unusual.
"I have no comment on this," said Ulrika Hjerpe at the Swedish Security Service (Säpo), regarding the move to raise security at the embassy.
Hjerpe pointed out that it is ultimately the embassy's decision on whether to take additional measures.
The Security Service issued a statement in November detailing the specific nature of the protection offered US officials in Sweden.
The Security Service has responsibility for the safety of the ambassador while Stockholm police are responsible for the embassy buildings and the vicinity.
The Security Service also underlined that it does not make public information regarding the level of threats directed against the US embassy.
"But globally speaking the security situation for the United States is different than for many other countries, and that is something the Security Service is naturally very aware of."
The US embassy concluded its Monday statement with the information that despite the heightened security, consular services will be available as normal and there would be no change to regular business hours.