The United States announced increased control over the security of its military in Europe

The European Command of the US Armed Forces, amid reports of the possibility of a terrorist attack on US military bases in Europe, is doubling the level of vigilance to ensure the safety of the country's military personnel stationed in the region and members of their families, an American military official told RIA Novosti.

"Due to a number of factors that could potentially impact the safety and security of U.S. military personnel and their families stationed in the European theater of operations, EUCOM has decided to redouble its level of vigilance during the summer months," the source said.

 CNN reported earlier Sunday that US military bases in Europe have been placed on high alert due to the threat of a terrorist attack - likely the highest in at least the last 10 years.