The Kremlin leader's remarks, which follow a feisty public appearance in which he compared the Kiev government to Nazis and warned the West not to "mess with us", came with Europe and the US preparing new sanctions to halt what they say is direct Russian military involvement in the war in Ukraine.
Ukrainian troops and local residents reinforced the port of Mariupol yesterday, the next big city in the path of pro-Russian fighters who pushed back government forces along the Azov Sea this past week in an offensive on a new front.
Ukraine and Russia have meanwhile swapped soldiers who had entered each other's territory near the battlefield, where Kiev says Moscow's forces have come to the aid of pro-Russian insurgents, tipping the balance on the battlefield in the rebels' favour.
Mr Putin said talks should be held immediately "and not just on technical issues but on the political organisation of society and statehood in southeastern Ukraine".
Moscow, for its part, he said, could not stand aside while people were being shot "almost at point blank".
Mr Putin's use of the word "statehood" was interpreted in Western media as implying backing for the rebel demand of independence, something Moscow has so far stopped short of publicly endorsing.
However, Putin's spokesman Dmitry Peskov said there was no new endorsement from Moscow for rebel independence. Asked if "New Russia", a term pro-Moscow rebels use for their territory, should still be part of Ukraine, Mr Peskov said: "Of course."
Rebels have rallied behind the term "New Russia" since Mr Putin first used it in a public appearance in April. Mr Putin called it a tsarist-era term for land that now forms southern and eastern Ukraine. Ukrainians consider the term deeply offensive and say it reveals Moscow's imperial designs on their territory.
Moscow has long called for Kiev to hold direct talks with the rebels. Kiev says it is willing to have talks on more rights for the south and east, but will not talk directly to armed fighters it describes as Russian puppets that can only be reined in by Moscow.
The deputy leader of the rebel Donetsk People's Republic, Andrei Prugin, said he was due to participate in talks in the Belarus capital Minsk today. Past talks by a so-called "contact group" involving Moscow, Kiev and rebels have covered technical issues such as access to the crash site of a Malaysian airliner shot down in July, but not political questions.
The past week has seen Ukrainian forces flee in the path of a new rebel advance, drawing concern from Ukraine's Western allies, who say armoured columns of Russian troops came to the aid of a rebellion that would otherwise have been near collapse.
EU leaders agreed on Saturday to draw up new economic sanctions against Moscow, a move hailed by the US which is planning tighter sanctions of its own and wants to act jointly with Europe.