Russia-Ukraine war: The symbols have appeared on many buildings in Kyiv.

The authorities in Ukraine are warning people to check for symbols on buildings, which could make them targets of the Russians. As the war intensifies, these symbols have been spotted on the rooftops of high rises and gas pipes in some cities.

Some of these symbols include a bright red X (X-marks-the-spot type) and arrows. Ukrainian authorities claim this is the work of “suspicious characters”, who are leaving clues for Russians, presumably for an airstrike. Some reports claim that reflective tags have also been found all around Kyiv.

The city of Kyiv, in a Facebook post last week, appealed to the people with access to roof to “urgently check” for such symbols.

“City authorities are appealing to residents of multi-storey buildings that have access to the roof, asking to urgently check the roofs for the availability of tags. In case any marks are detected – please put them to sleep with the ground or something to cover,” it said in the post.

Alexander Tretyak, the mayor of Rivne, a town in western Ukraine, posted a similar message on his official Facebook page.

“URGENT ANNOUNCEMENT! I ask the heads of the condominiums to close all attics. If you or a resident of the house notice tags in the driveway, on the roof, next to the houses of unknown persons – inform law enforcement immediately,” he said in the post.

“URGENTLY check your roofs, in case you find the tags paint them and close access to the roofs,” Tretyak further said.

Despite tough sanctions announced by the West, Russia showed no sign of stopping the invasion of Ukraine, where fierce fighting and Russian bombardment have killed dozens and sparked a refugee crisis.

Both the sides held talks on Monday to discuss ceasefire, but no breakthrough could be achieved.

Ukraine’s Western allies have increased weapons transfers in support, and Britain has called for such transfers to be expanded. Finland agreed to ship 2,500 assault rifles and 1,500 anti-tank weapons. Canada will supply anti-tank weapons and upgraded ammunition, Prime Minister Justin Trudeau said.