- 40 updates
Rebels in Ukraine have released four more international observers in the eastern city of Donetsk, according to reports.
The observers from the Organisation for the Security and Cooperation in Europe (OSCE) were captured by pro-Russian separatists over a month ago.
A ceasefire in eastern Ukraine has been extended for three more days, the Ukrainian president's office has said.
President Petro Poroshenko's office said that the week-long cease-fire that ended today has been extended until 10pm local time on Monday.
A leader of pro-Russian insurgents said today they would also extend the ceasefire if Mr Poroshenko does so.
Russian president Vladimir Putin has urged both sides in the Ukrainian conflict to sit down at the negotiating table and find a compromise.
He said such a compromise must guarantee the rights of Russian-speaking residents of eastern Ukraine, who must feel like they are "an integral part" of Ukraine.
Russian President Vladimir Putin said that he supported Ukraine President Petro Poroshenko's call for a ceasefire, but added that without "practical actions" to start negotiations the plan would not be viable.
Russia's President Vladimir Putin has said that he supports the Ukrainian President Petro Poroshenko's decision to call a ceasefire, according to a Kremlin statement.
However, he said the plan will not be viable without "practical actions" to start the negotiation process.
A unilateral ceasefire called for by Kiev is under pressure after pro-Russian separatists attacked an Ukrainian military base and posts on the border with Russia, government forces said.
The fresh attack came just hours after the start of a ceasefire at 10 p.m. on Friday by Ukrainian forces, ordered by President Petro Poroshenko as part of his plan to end the rebel insurgency in the east of the country.
Russia could face the threat of fresh sanctions unless it fails to defuse tensions on the Ukraine border, the White House has warned.
The US claimed it has intelligence suggesting Russia was accumulating tanks and military forces near its border with Ukraine.
US President Barack Obama spoke with both French President Francois Hollande and German Chancellor Angela Merkel after Ukraine's president declared a week-long ceasefire in its fight against pro-Russian separatists.
Russia dismissed Petro Poroshenko's plan, claiming it was an "ultimatum" rather than an offer of peace.
After President Obama's conversations with the respective leaders, a statement said: "They agreed that should Russia fail to take immediate, concrete steps to de-escalate the situation in eastern Ukraine, the US and the European Union would coordinate additional steps to impose costs on Russia."
Ukrainian president Petro Poroshenko met soldiers at a military camp in eastern Ukraine as he announced a week-long ceasefire with pro-Russian separatists today.
The US State Department said it was told Russia has accumulated tanks and artillery at deployment sites that may be given to separatist fighters in Ukraine.
The US also has its own information that Russia redeployed military forces to its border with Ukraine, State Department spokeswoman Jen Psaki said.
"We have information that additional tanks have been prepared for departure," she added.
Foreign Secretary William Hague wrote on Twitter: