SLAVYANSK, Ukraine (AFP) ― Ukraine on Tuesday brushed off strong European pressure and rejected talks with pro-Russian rebels on a truce to halt a bloody insurgency shaking the ex-Soviet nation until they lay down their arms.

The unconditional stance reflected a new confidence in Kiev that it was on the verge of quashing an uprising it views as Moscow’s retribution for the February ouster of a Kremlin-backed leader and the decision to pursue a historic alliance with the West.

But it was also bound to frustrate EU leaders’ push for a diplomatic solution as well as the Kremlin’s own efforts to force Kiev to make compromises that would preserve the Russian-speaking east’s links to Moscow.

“Now, any negotiations are possible only after the rebels completely lay down their arms,” Defense Minister Valeriy Geletey said in a statement.

Ukrainian forces have scored a string of surprise military successes since the weekend that forced most of the militias to retreat to the sprawling eastern industrial hubs of Donetsk and Lugansk ―both capitals of their own “People’s Republics.”

President Petro Poroshenko has ordered his troops to blockade the insurgents inside the cities and cut them off from any further arms supplies. The new Western-backed leader said during an unannounced visit to Slavyansk ― a former rebel bastion reclaimed by Kiev on Saturday ― that talks with the uprising’s commanders were impossible because most were now hiding in Moscow.

Poroshenko told reporters that he would only speak “to the real masters of (the eastern region of) Donbass ― the steel workers and miners, people who hold the most power” in the conflict zone.

But it was not immediately clear how he intended to force the militias to give up their three-month campaign to join Russian rule.

Lugansk separatist leader Valeriy Bolotov claimed that his men had managed to actually push back Ukrainian troops from part of the Russian border city and receive fresh supplies of antiaircraft and artillery guns.

Poroshenko tore up a 10-day ceasefire on July 1 because of uninterrupted rebel attacks that claimed the lives of more than 20 Ukrainian troops.

Uneasy EU leaders are hoping that a new truce and a Kremlin promise not to meddle can take pressure off the bloc to adopt sweeping sanctions that could damage their own strong energy and financial bonds with Russia.

French President Francois Hollande said he intended to press Poroshenko on Wednesday during a joint call with German Chancellor Angela Merkel.

But Washington has consistently backed the stepped-up campaign being waged by Ukrainian troops and irregular forces since Poroshenko’s promise after his election in May to quickly quash an uprising that has cost nearly 500 lives and inflamed East-West ties.

The United States views Ukraine’s territorial integrity as vital to European security and important to halting Russian President Vladimir Putin’s seeming ambition to resurrect a tsarist or post-Soviet empire.

U.S. State Department spokeswoman Jen Psaki reiterated on Monday that “the government of Ukraine is defending the country of Ukraine, and I think they have every right to do that.”

Poroshenko on Tuesday dismissed the man who had headed Kiev’s self-proclaimed “antiterrorist operation” since its launch on April 13 and replaced him with Vasyl Grytsak ― a career security service officer.

The reshuffle was one of several in the Ukrainian Security Service and appeared to represent an attempt by Poroshenko to place trusted associates in top positions rather than any change of tactics in the campaign.

Germany’s Berenberg Bank economist Holger Schmieding said Putin now faced a tough choice between dealing a blow to Russia’s economy by further boosting support for the rebels or seeing his own popularity suffer by taking no action at all.

“He may either have to step up his support for the pro-Russian insurgents who are now on the defensive; or he may be seen as letting Ukraine advance on the ground in Donbass,” Schmieding wrote in reference to the eastern Lugansk and Donetsk regions.

“The former could trigger more serious sanctions and further capital flight from Russia. The latter could hurt his popularity and his ‘strongman’ image in Russia, where (he) had whipped up nationalist sentiment in the last five months.”