Representatives of the contact group on Ukraine agreed a ceasefire at talks in Minsk on Tuesday, Russia's TASS news agency reported, but a rebel envoy to the talks said it was too early to say a deal had been reached.TASS, quoting an unnamed source, said the representatives from Russia, Ukraine, pro-Russian rebels and the OSCE security watchdog agreed a ceasefire for east Ukraine, a monitoring mechanism and a scheme for withdrawal of heavy weapons.They were meeting ahead of Wednesday's summit of leaders of Russia, Ukraine, France and Germany who will try to broker a peace deal in the conflict, which has killed more than 5,000 people.There was no confirmation of the TASS report from those taking part in Tuesday's contact group meeting.Speaking after the talks seemed to have ended on Tuesday, a rebel envoy Denis Pushilin said he had handed over to the Ukrainian representatives a proposal of "political and military steps" towards de-escalation and that the talks would resume after the Ukrainian side considers them. He did not say whether the talks would continue on Tuesday or later on.Any failure in the contact group talks would bode ill for Wednesday's four-way summit, which comes as the pro-Russian rebels pressed on with an assault on an army-held rail junction. .