Red and white posts mark the line of a fence that is to be built between Belarus and Lithuania.
Lithuanian guards began building the first stretch of a barbed-wire barrier last week.
They have accused Belarus authorities of sending migrants illegally over the border, so that they can travel onwards to the more affluent west of the European Union.
Lithuania is an EU member and the bloc hit Belarus with sanctions for forcing a Ryanair flight to land then arresting a dissident blogger on board.
Belarus responded by allowing the migrants to enter the EU through its neighbor's border.
Lithuania's barrier will stretch for 320 miles, six feet high.
Public Affairs Officer of Lithuanian Armed Forces, Andrius Dilda:
"It's an obstacle for the crisis that our border patrols are currently facing. So, it will help them a bit to control that most critical place or distance on the border."
He told Reuters they are also bolstering the border with additional personnel.
On Tuesday Lithuania's parliament also approved the mass detention of migrants and curbed their right of appeal, a move meant to deter high numbers.
The new law bans any release of migrants from detention for six months after their arrival.
The fence will cost around $6 million US dollars.
More than 1,700 people crossed the frontier this year, including 1,100 in July alone.