By Richard Balmforth and Natalia Zinets
KIEV (Reuters) - Ukrainian President Petro Poroshenko accepted on Sunday the resignation of his defense minister who has been under fire over a rout of government forces in the east which led to Kiev calling a ceasefire with pro-Russian separatists.
Poroshenko's website said the president had accepted the offer of resignation from Valery Heletey, 47, whom he appointed only in July. It said Poroshenko hoped to present a new ministerial candidate to parliament on Monday.
Poroshenko, meanwhile, said he was braced for talks with Russian President Vladimir Putin in Milan later this week." I don't have illusions. These will be difficult talks. But I am ready," he said, according to his website.
Heletey, who formerly led a presidential bodyguard unit, had drawn heavy criticism since the crushing defeat of Ukrainian forces at Ilovaisk, east of the main rebel-held eastern city of Donetsk, in late August.
Kiev says more than 100 Ukrainian troops and members of pro-government volunteer battalions were killed when they were hemmed in by an unexpected attack from Russian forces supporting the separatists. Large numbers of Ukrainians were also taken prisoner by the rebels.
Ukrainian military sources say a large number of Russian troops were also killed - a charge not acknowledged by Moscow, which denies any part in the Ukraine conflict despite what Kiev and Western governments say is incontrovertible proof.
Analysts say the Aug. 24 attack led Poroshenko reluctantly to accept that Kiev could not beat the separatists militarily as long as they were supported by direct involvement of Russian troops and equipment.
A ceasefire negotiated by Kiev, Moscow and the rebels came into force on Sept. 5. It is still broadly holding despite sporadic violations, especially around Donetsk airport, which is still defended by government forces.
Poroshenko expressed optimism for a full ceasefire. "The number of victims is falling ... We reckon that we'll have a full ceasefire in a few days," he said.
Heletey is the third defense minister to be appointed since the ousting in February of Ukraine's previous president, Moscow-backed Viktor Yanukovich, by mass street protests in support of closer ties with the European Union.
When Poroshenko appointed him in early July, Heletey made an ambitious but unrealistic promise that Ukrainians would see a future victory parade in Crimea, the Black Sea peninsula Russia had annexed in March in response to the ousting of Yanukovich.
But since July, Russian-backed armed resistance to Kiev's rule has only grown in eastern Ukraine, with government forces losing more ground near the Sea of Azov in the southeast.
Heletey, in a fierce debate last week, defended his handling of the fighting in Ilovaisk, insisting that despite their losses Ukrainian forces had inflicted heavy casualties on the adversary which he said had "stopped Putin".
Poroshenko is hoping that an Oct. 26 parliamentary election will produce a coalition to support his peace policies.
But he faces internal opposition from parties who fear he may make too many concessions to the separatist leaders in the heavily industrialized, mainly Russian-speaking east, who are pressing for unity with Russia.
The United Nations says more than 3,600 people - Ukrainian troops, separatists and civilians - have been killed in eastern Ukraine since the fighting erupted there in April.
(Additional reporting by Natalia Zinet; Editing by Robin Pomeroy)