LVIV, March 14 - Russia’s forces pounded away at Kyiv and other cities across the country on Monday in a punishing bombardment the Red Cross said has created “nothing short of a nightmare” for civilians, The Associated Press reported.

A convoy of 160 civilian cars left the encircled port city of Mariupol along a designated humanitarian route, the city council reported, in a rare glimmer of hope a week and a half into the lethal siege that has pulverized homes and other buildings and left people desperate for food, water, heat and medicine.

Russia and Ukraine kept a fragile diplomatic path open with a new round of talks Monday. The latest negotiations, held via video conference, were the fourth round involving higher-level officials from the two countries and the first in a week. The talks ended without a breakthrough after several hours, with an aide to Ukrainian President Volodymyr Zelenskyy saying the negotiators took “a technical pause” and planned to meet again Tuesday.

The two sides had expressed some optimism in the past few days. Mykhailo Podolyak, the aide to Zelenskyy, tweeted that the negotiators would discuss “peace, ceasefire, immediate withdrawal of troops & security guarantees.”

Overall, nearly all of the Russian military offensives remained stalled after making little progress over the weekend, according to a senior U.S. defense official who spoke on condition of anonymity to discuss the Pentagon’s assessment. Russian troops were still about 15 kilometers (9 miles) from the center of Kyiv, the official said.

The official said that Russian forces have launched more than 900 missiles since the start of the invasion, but that Ukraine’s airspace is still contested, with Russia not achieving total air superiority.

Overnight, air raid alerts sounded in cities and towns around the country, from near the Russian border in the east to the Carpathian Mountains in the west, and fighting continued on the outskirts of Kyiv. Ukrainian officials said Russian forces shelled several suburbs of the capital.

Ukrainian authorities said two people were killed when the Russians struck an airplane factory in Kyiv, sparking a large fire. The Antonov factory is Ukraine’s largest aircraft plant and produces many of the world’s biggest cargo planes.

Russian artillery fire also hit a nine-story apartment building in the northern Obolonskyi district of the city, killing two more people, authorities said.

Robert Mardini, director-general of the International Committee of the Red Cross, said the war has become “nothing short of a nightmare” for those living in besieged cities, and he pleaded for safe corridors for civilians to leave and humanitarian aid to be brought in.

“The situation cannot, cannot continue like this,” he said. “History is watching what is happening in Mariupol and other cities.” (ap/ez)