Delegations from Kyiv and Moscow have begun talks at the Ukraine-Belarus border, the foreign ministries of both countries have confirmed.

Ukraine said its goal for the talks is an “immediate ceasefire and withdrawal of Russian troops” from Ukrainian territory.

Al Jazeera reports that Kyiv has sent a delegation of several high-ranking officials, but the president, Volodymyr Zelenskyy, is not joining the discussion.

Russian negotiator Vladimir Medinsky said Russia wants to reach an agreement that is in the interest of both sides.

The negotiation comes five days after Russian President Vladimir Putin launched a full-scale invasion of Ukraine. Analysts said it is the biggest attack on a European state since the second world war.

By Monday afternoon, Ukrainian soldiers were still trying to resist Russia’s advances. In the face of stiff resistance and devastating sanctions, Mr Putin set Russia’s nuclear forces on high alert, threatening to elevate the war to a terrifying new level.

Russia has made some military gains in southern Ukraine, experts told Financial Times, but “the pace of its advance has slowed and it is yet to take any big Ukrainian population centres, with the capital Kyiv still under government control.”

Mr Zelensky said on Monday that Ukraine was braced for a crucial 24 hours, as Russian troops stepped up efforts to encircle the capital.

The bulk of Mr Putin’s ground forces remained more than 30km north of Kyiv, according to an assessment by the UK defence ministry, their advance frustrated by logistical failures and staunch Ukrainian resistance.

Reinforcements were expected on Monday to buttress what appears to be Russia’s objective of taking Kyiv to force a surrender, the Financial Times reports

Heavy fighting continued around Kharkiv, although media reports suggested that the second largest city remained in government hands.

In southern Ukraine, Russian attempts to cut Ukraine off from the Black Sea appeared to be having more success. Its forces have captured the towns of Berdyansk, on the Sea of Azov, and Enerhodar, according to a Russian defence ministry statement seen by Financial Times.

“Reports suggested that the port of Mariupol, the last big stronghold of Ukrainian resistance that has stopped Russia from connecting the eastern border region of Donbas to Crimea, was surrounded.”

Russia’s defence ministry added that its troops had seized territory around a nuclear power plant in Zaporizhiya and that Russia now controlled all of the Ukrainian airspaces.

Ukraine’s military confirmed Russian troops continued to attack airports, air defence systems, critical infrastructure and residential areas around the country and had launched missile strikes on buildings in the cities of Zhytomyr and Chernihiv.

The exact death tolls are unclear as of Monday, but the United Nations (UN) has said 102 civilians have been killed and hundreds wounded. The UN however said the figure is likely a vast undercount.

More than 500,000 people have fled Ukraine while about 3 million require humanitarian aid, according to the UN.