President Vladimir Putin hosted US ­Secretary of State John Kerry for high stakes talks Tuesday as Washington seeks the full implementation of a shaky Ukraine cease-fire and renewed efforts to end the Syrian war.

On the highest-level US visit to ­Russia since the conflict in Ukraine erupted in late 2013, Kerry first met with his ­Russian counterpart Sergei Lavrov for four hours in the Black Sea resort of Sochi before being welcomed by Putin at his seaside summer residence.

The two men warmly shook hands before sitting down with a small team of staff at a long table.

At "a critical moment" for Ukraine, Washington is looking to ensure the "next steps in concrete ­implementation" of the truce deal, as well as to "see ­whether they (Russia) see an ­opportunity to do more together" in Syria, a senior State Department official said.

Kerry was also set to discuss ­Yemen and Libya and brief Putin on the ­negotiations on curtailing Iran's nuclear program.

He was accompanied by chief US negotiator Wendy Sherman who will travel to Vienna on Wednesday for a new round of Iran talks.

After top US officials snubbed Putin's huge military victory parade on Sunday, Kerry and Lavrov shared a poignant moment when, watched by dozens of schoolchildren, they laid wreaths at a World War II memorial to mark 70 years since the defeat of Nazi Germany.

Ties between Moscow and ­Washington collapsed when ­Russia seized the southern Ukrainian ­peninsula of Crimea in early 2014 and later was ­accused ­buttressing the rebels in eastern Ukraine.

But after a year of tensions, signs are emerging that both Russia and the West may be ready to seek detente.

And on a host of global issues - from the threat of Islamic militants in Iraq to the civil war in Syria where US-backed Syrian rebels are seeking to oust ­President Bashar al-Assad - Washington aims to engage Moscow's help.

"We have a lot of business we could do together if there is interest," the ­senior State Department official told ­reporters travelling on Kerry's plane.

Kremlin spokesman Dmitry ­Peskov described the visit by Kerry as ­"extremely positive" and said that his talks with ­Putin would cover a wide range of ­topics, from US-Russian ­bilateral ties to other international "hot-­button issues."

"Through dialogue we can search for a path towards some sort of ­normalization of ties and closer ­coordination in solving international problems," Peskov was quoted as ­saying by Russian wires. "But this is only ­possible through dialogue."

Putin has refused to budge on Ukraine, despite a cease-fire agreement re-negotiated in February in Minsk, but has signaled readiness to mend ties with Washington and Brussels.

Kerry's visit comes hot on the heels of German Chancellor Angela Merkel, who has led European efforts to broker a peace deal in Ukraine and who said in Moscow on Sunday that there was still no genuine cease-fire.