The occupation lasted just a few hours and appeared to be an attempt to destabilise the supply lines of the Kosovo Liberation Army, which uses the border region to run training camps and smuggle weapons into Kosovo. The incursion was denied by Belgrade but heightened fears that the conflict is in danger of spreading.
"We have seen houses burning, we have seen the flames," said Pier Gonggripj, head of the Organisation for Security and Co-operation in Europe (OSCE) monitoring office in Bajram Curri, the largest town in the area where Serb forces launched their assault.
The town is only eight miles from the border, and the monitors, standing on the roof of their hotel, were able to watch Kamenica burning until low cloud obscured the view.
By mid-afternoon, a few Albanian soldiers hung around at a crossroads about five miles from Kamenica, gazing at the tiny settlement perched in a clearing under a ridgeline. It was barely visible because of the persistent drizzle and clouds.
"It is too dangerous to go any further," said Captain Qamil Katuroshi, as two Kosovo rebels trotted up on a pair of ponies, then cantered off up the road under the gaze of a television camera. "The situation was terrible. Now it's quieter."
Mr Gonggripj and his OSCE monitors had a running commentary of the incident, since they were listening in to the Albanian border guards' radio frequency. "Shortly before 1 o'clock there was some shelling with mortars of Kamenica - that was nothing new because it has been happening for the last three days," Mr Gonggripj explained.
"Then at about 1.10 we heard ... them saying that the Yugoslav light infantry had crossed the border and were advancing on the border police post. They were already firing their weapons. The border police chief ordered them [the border guards] to open fire against the intruders."
The chief's actual words were: "Be a man, we will support you." Then, he warned his men against getting surrounded and advised them to withdraw. "At 1.20... we heard
on the radio that the Yugoslav soldiers - there were about 50 of them - had reached the house where our sub-office used to be and then one minute later that they had reached the Kamenica border post," Mr Gonggripj added.
Within 10 minutes came the news that the Yugoslav forces were retreating from the village and that there were no Albanian casualties. The Albanian army fired artillery at the enemy forces - "the first time of any response from the Albanian side", according to Mr Gonggripj. He supports the Albanian line that the KLA is not active in Kamenica - although observers speculate that the assault might have come in reprisal for KLA attacks elsewhere. Capt Katuroshi, among others, claimed the KLA had won control of the Koshara border post, attacking the Serbs from inside Kosovo. The OSCE has heard rumours to this effect, but has no confirmation of the incident.
Monitors have reported eight KLA dead and eight wounded from fighting in Kosovo, including four soldiers who crossed into a minefield.
The assault will have the effect of scaring people away from the border region, which will suit the Serbs, who want free rein to pursue the KLA.
Frightened civilians from Tropoje and another village, Vichidol, walked along the muddy track towards Bajram Curri, herding sheep, goats and cattle too valuable to be left behind in case of another Serbian attack. Two donkeys overloaded with bundles of possessions plodded through the rain while their owner wandered behind, sheltering under a large umbrella.
In Tropoje where three people have been killed and 16 wounded by Serb shells in the past few days, Ziz Shabani, 61, and other villagers are living underground in an L-shaped bunker perhaps 2 metres wide and 2 metres high. "We are hiding here because the Serbs are shelling our village - we are afraid," she said, gesturing to the camp beds covered in grey blankets that now furnish the shelter, and which they moved into shortly after the first Nato air strikes drew retaliatory Serb shelling.
Gjyl Mula was finishing her packing, to head out for the capital, Tirana, a journey that will cost $200 (pounds 126) "We are going because we have been living in the bunker for 17 days and we are still afraid. We have no family there, we are going like refugees," she said.