Jordan's army said border guards killed 12 people, injured a number of others, when clashing with a group of people trying to cross from Syria into Jordan on Saturday.
A group of 36 people, some carrying weapons, tried to enter the Kingdom in an attempt to escape the conflict-ridden country. Some of them fled back to Syria after clashing with the border guards, according to information on the Jordanian military's website.
An armed forces general command official said more than two million pills of narcotics were also seized.
Jordan regularly voices fears of terrorists infiltrating refugee groups to justify curbs on Syrian refugees awaiting entry to the country at the border, estimating their number to be 17,000.
The situation has become much worse since Russia launched its air campaign on September 30 in support to Syrian regime leader Bashar al-Assad.
Moscow says its air strikes target DAESH terror group but has been accused of mainly targeting Western-backed opposition groups.
"When Russia entered the crisis there was a much bigger inflow of refugees and wounded," Brigadier General Saber al-Mahayreh, commander of Jordan's Border Guard, told reporters.
The Syrian Observatory for Human Rights (SOHR) reported on Wednesday that at least 3,000 people including more than 1,000 civilians have been killed in Russian air strikes since September.
Jordanian government figures put the number of Syrians to have entered the country after fleeing the conflict at more than 1.4 million.