Trailed by a convoy of cars waving the Ukrainian flag and honking their horns, two buses carrying observers from the Organisation for Security and Cooperation in Europestopped dead at a checkpoint flying the Russian colors.
For the second day in row, 47 military and civilian observers from OSCE were hoping to make their way into Crimea on Friday to defuse tensions in the flashpoint Ukrainian peninsula.
But again they were forced to turn back by armed men blocking one of only two main roads that attach the Black Sea region to the rest of the country.
Led by a Ukrainian police car, the convoy of two buses and about 100 cars approached the improvised roadblock near the village of Chongar around 3:00 pm local time.
Forced to stop by concrete slabs interspersed on the road, the observers waited as attempts were made to convince the armed men to allow the convoy through.
Out of the cars spilled dozens of people, waving flags and chanting "Crimea is Ukraine!"
"We don't want Ukraine to be split, the OSCE is able to negotiate, we want a decision to be made peacefully," said one of the demonstrators, 55-year-old Lyudmila Korbec.
As the crowd gathered between the buses and the checkpoint, tensions started to mount.
Eventually one of the demonstrators shouted out above the crowd, urging them to leave and warning of a possible "provocation".
The crowd thinned as the demonstrators drove back the way they came. A source within the OSCE mission said talks were continuing.
But it soon became clear that there was no way the armed men, their faces hidden behind balaclavas, were going to allow the convoy through.
The buses turned around and returned to the city of Kherson, where the team had spent the night after being blocked from entering Crimea a first time on Thursday.
"They didn't allow us to enter and recommended we talk to the government of Crimea. They said the Crimean government didn't invite the mission," said a Ukrainian military officer traveling with the convoy.
"Discussions are to be held on whether we will make another attempt."
The unarmed observers, from 25 of the organization's 57 members, have been invited by Ukraine's new government for a mission aimed at monitoring the situation and lowering tensions in Crimea.
Russian forces have surrounded Ukrainian military bases on the peninsula and local lawmakers have decided to renounce ties with Ukraine and stage a March 16 referendum on switching over to Kremlin rule.
Jutting into the Black Sea, Crimea is easy to isolate from the rest of Ukraine.
Only two main roads lead into the peninsula, one crossing the narrow Isthmus of Perekop in the west and another eastern route on the Azov Sea.
At the checkpoint near Chongar, which is on the eastern route, it appeared that preparations were being made for a more permanent border to be put in place.
Spreading out from the road by the checkpoint was a perfect row of holes dug into the earth, each about 18 inches wide, in what looked like the first steps of installing a border fence.
Signs nearby warned of mines and were marked "Stop! Danger to Life!" with a skull-and-crossbones.