* Kiev's ceasefire due to expire at 1900 GMT
* Poroshenko meets his security chiefs to discuss next step
* Talks with Russian, French, German leaders (Adds Ukraine security meeting, quote, changes dateline to KIEV)
KIEV, June 30 (Reuters) - Ukrainian President Petro Poroshenko called a meeting of his security chiefs on Monday to decide whether to extend a shaky ceasefire in the war against separatists that was due to lapse at 10 p.m. (1900 GMT).
Poroshenko went into a session of the national security and defence council after four-way telephone discussions with the leaders of Germany, France and Russia aimed at helping end the situation in Ukraine's Russian-speaking east where government forces have been battling pro-Russian separatists since April.
Earlier, the French president's office said Poroshenko and Russia's Vladimir Putin had agreed to work on a new ceasefire between the opposing sides, work to set up effective border controls and free more hostages and prisoners on both sides.
There was no word from the Ukrainians on how the talks went.
But as Poroshenko began meeting his security chiefs he was facing calls from some of them not to extend the ceasefire beyond the Monday 10 p.m. deadline because of Ukrainian military losses in the past seven days.
Before going into the meeting, Vitaly Yarema, the prosecutor-general, said: "We have to end this and clean our territory of terrorists and give people the chance of living in a normal country."
Poroshenko extended the original week-long ceasefire by 72 hours last Friday at the urging of the West and Russia, but many on the government side say the separatists are using the time to re-group and rearm.
At least 18 Ukrainian members of the military, including nine on board a helicopter downed by the rebels on June 24, are reported to have been killed during the ceasefire.
After what French President Francois Hollande said was a long conversation also involving German Chancellor Angela Merkel, Poroshenko and Putin agreed to work on a ceasefire between separatists and the Ukrainian authorities and on quickly setting up effective border controls, his office said.
Putin and Poroshenko also agreed to work on freeing more hostages and prisoners and the organisation of "substantial tripartite negotiations", according to the statement.
Poroshenko had urged Putin on Sunday to strengthen Russian control over its borders to prevent militants and arms entering Ukraine after violence led to breaches of a truce there.
The European Union, which signed a landmark free-trade pact with Ukraine on Friday, has warned it could impose more sanctions unless pro-Russian rebels act to wind down the crisis in the east of the country by Monday.
Putin again urged that the ceasefire in eastern Ukraine be extended and a control mechanism to monitor the truce set up, with the participation of the Organisation for Security and Co-operation in Europe, the Kremlin said in a separate statement after the talks.
"The leaders spoke in favour of convening a third round of consultations between Kiev and south-eastern regions as soon as possible," it added.
Hollande's office said Russia's and Ukraine's foreign ministers would be in touch later and that a contact group on Ukraine would meet to discuss implementing agreed moves.
Speaking after the presidents' call, Russian Foreign Minister Sergei Lavrov told Russian state TV that Moscow was ready to allow monitors from the OSCE security and rights watchdog and Ukraine's border guards to the Russian side of the border for joint control. (Reporting by Ingrid Melander in Paris; and Gabriela Baczynska in Moscow, Additional reporting by Elizabeth Pineau in Paris; Writing by Richard Balmforth; Editing by Robin Pomeroy)