Russia, Ukraine, the US and EU reached a surprise deal Thursday on de-escalating the worsening Ukrainian crisis, in a ray of hope for the former Soviet republic that has plunged into chaos.
The agreement reached in Geneva comes as a strong contrast to earlier hawkish comments made by Russian leader Vladimir Putin, who left the door open for intervention in Ukraine.
A ban by Kiev on all Russian males aged 16 to 60 from entering Ukrainian territory had also ratcheted up the tensions, with Russian foreign minister Sergei Lavrov calling the measure "disgusting".
But after half a day of talks, the four parties agreed on steps to "restore security for all citizens", including a call to disband armed groups that have taken over buildings in Ukraine "illegally".
While not spelt out in the agreement, these groups could refer to pro-Kremlin separatists who have seized control of government buildings and taken over parts of Ukraine's southeast, destabilising the country.
"All illegal armed groups must be disarmed, ilegally seized buildings returned to their rightful owners," Lavrov said as he briefed reporters about the deal reached with US secretary of state John Kerry, Ukraine's Andriy Deshchytsya and EU foreign policy chief Catherine Ashton.
Washington and Kiev have accused Russia of supporting the militants who have occupied buildings such as police stations and government bases, but Moscow has always categorically denied this.
Lavrov also said Russia had "no desire" to send troops into Ukraine, toning down earlier comments by Putin.
Warning that Ukraine was plunging into the "abyss" just hours after three separatists were killed in a gunbattle with troops in eastern Ukraine, Putin had stressed he hoped not to have to use his "right" to send Russian troops into its western neighbour.
"I very much hope that I am not obliged to use this right and that through political and diplomatic means we can solve all the acute problems in Ukraine," he said in his annual televised phone-in with the nation, in a signal the option was on the table.
The upper house of parliament on March 1 authorised the Russian leader to send troops into Ukraine after pro-Kremlin president Viktor Yanukovych was ousted, and Moscow later went on to annex Ukraine's Russian-speaking Crimean peninsula.
Russia has now massed tens of thousands of troops at the border and has warned Kiev's untested new leaders -- whom it does not recognise as legitimate -- not to unleash force in Ukraine.
Accordingly, Kerry warned Russia that if there was no progress on de-escalating the crisis in Ukraine, "there will be additional sanctions, additional costs."
The United States and European Union have already imposed punitive sanctions on key Russian and Ukrainian political and business officials, including members of Putin's inner circle.
And the European Parliament on Thursday said the European Union should act "against Russian firms and their subsidiaries, especially in the energy sector, and Russia's EU assets".
So far, though, any further sanctions appear to have been put on hold.
Russia's annexation of the Crimea peninsula last month escalated a crisis that has shaped up to be the worst East-West standoff since the Cold War.
On Thursday, Kerry said the West is "not giving up" on peninsula, "but we did not come (to Geneva) to talk about Crimea."
Each side came to the Geneva talks armed with a very specific set of demands, and the West and Kiev had aimed to persuade Moscow to demobilise the militias.
Ukraine's Security Service said it was detaining 10 "Russian spies" arrested over the past six weeks on suspected missions to stir up unrest in the country, further implying Russia's role in the destabilisation of the country.
But Russia has blamed Kiev's interim leaders -- installed by Ukraine's parliament in February after the overthrow of Yanukovych following months of protests -- for pushing the country dangerously close to a civil war.
The agreement also called on all sides to refrain from violence, intimidation and provocation, as well as to reject extremism in all shapes.
Kerry told reporters that notices were sent to Jews in a Ukrainian city believed to be in the east, asking them to identify themselves as Jews -- a move he condemned as "grotesque".
"In the year 2014, after all of the miles travelled and all of the journey of history, this is not just intolerable, it's grotesque. It is beyond unacceptable," he said.
Separately, the European Union announced Thursday it had agreed to hold talks with Russia on its gas supplies to Europe through Ukraine, warning Moscow its reliability as an energy source was at stake.
The announcement came even as Putin ramped up pressure on Ukraine by setting a one-month deadline for Kiev to settle its debt for gas imports from Russia.