Insurgents have been battling to try to enter Hama since Tuesday, and there was heavy fighting overnight.
Russia targets German helicopter in Baltic Sea, triggering concerns over hybrid warfare tactics.
Bulgarian nationals Katrin Ivanova, 33, Vanya Gaberova, 30, and Tihomir Ivanchev, 39, are accused of being part of a sophisticated spying network run by a Russian agent named Jan Marsalek.
The US bombers were in the Baltic Sea region to train together with their NATO ally Finland, which shares a 1,340 km (833 miles) border with Russia.
Previous reports emerged that Russia has sought after foreign mercenaries from countries with "difficult economic situations" to fight in Ukraine.
The Kremlin said that it had "no doubt" that Washington understood its messaging behind Thursday's attack in central Ukraine.
Jake Reeves, 22, pleaded guilty at London's Woolwich Crown Court to charges of aggravated arson on the premises belonging to a "Mr X" on an industrial estate in east London in March.
Ukrainian Prime Minister Volodymyr Zelensky says the Russian missile strike with new weapon is a clear escalation of the 33-month-old war.
Civilian populations are allowed and even encouraged to flee combat zones to avoid danger. Why can't Gazans?
The launch was the latest sign of rapidly mounting tensions in the 33-month-old war after Ukraine fired US and British missiles at targets inside Russia.