A senior army officer said on Wednesday that Jordan can defend itself against "any aggression" after Sunni Arab militants seized large swathes of neighbouring Iraq.
"The Jordanian-Iraqi borders are safe. The Jordanian armed forces are capable of defending the kingdom from any aggression," border guard commander Brigadier Saber Mahayrah told reporters as they toured the border area.
"We will not allow anyone to cross illegally," he said as armoured personnel carriers, Humvees and tanks deployed to the area.
Four military helicopters hovered over the border.
Mahayrah made his remarks two days after Jordan reinforced its border.
"The Jordanian army has dispatched more troops, tanks, rocket launchers and armoured personnel carriers to the border with Iraq," a security official told AFP on Monday.
"The army will not tolerate any kind of infiltration."
Sunni insurgents led by the jihadist Islamic State of Iraq and the Levant (ISIL) overran swathes of land north and west of Baghdad this month.
There is only one official crossing between Iraq and Jordan, at Trebil, some 370 kilometres (230 miles) east of Amman.
There was confusion over who controls the Iraqi side of the crossing, with some reports saying ISIL fighters have overrun it and others saying it is under the control of Sunni tribes.
"The crossing post on the Iraqi side is run by Iraqi government officials. It is working normally," said an Iraqi driver as several trucks crossed into Jordan.
The Sunni militant offensive in Iraq has sparked fears in Amman that the jihadists will take their fight to Jordan.
Already struggling to cope with hosting more than 600,000 Syrian refugees, Jordan has long faced a challenge in dealing with its own jihadists, many of whom have joined ISIL or Al-Qaeda-linked groups in neighbouring Iraq and Syria.