The new president of the European Council could be "very important" for David Cameron.
The mother of the three Australian children killed on flight MH17 told a memorial service her "arms would always be reaching for them."
A woman has apparently posted pictures of herself on social media with mascara looted from the Malaysian Airlines flight MH17 crash site.
President Obama is in Estonia for talks with Baltic leaders about the crisis in Ukraine.
The leaders of Estonia, Latvia and Lithuania are reportedly concerned about possible Russian aggression following the recent intervention in Ukraine.
Mr Obama will then travel to the Nato summit in south Wales where leaders from the military alliance are expected to support a new rapid-reaction force to respond to any Russian action in eastern Europe.
The European Union will tomorrow discuss yet more sanctions against Russia - to try to end President Putin's support for rebels in Ukraine.
There's been evidence of that support in one of the key battle grounds - the town of Ilovaisk from where ITV News Europe editor, James Mates reports:
The Prime Minister has called on Nato members to send a "very clear, unified and strong message" in response to the crisis in Ukraine.
Speaking at a reception for the Nato Parliamentary Assembly at Downing Street, David Cameron said: "Members of Nato want and deserve real reassurance that our Article V commitments are rock solid."
Article V refers to one of the founding principles of the Nato alliance stating that if one of its members is attacked, it "shall be considered an attack against them all".
UK Foreign Secretary Philip Hammond said Nato needs to show a political will to fight back if Russia was to attack any of the alliance's members.
Mr Hammond said Nato leaders needed to make clear there was a "red line" around the 28 member states which could not be crossed.
His comments come ahead of a Nato summit in Wales this week.
Meanwhile, several former Eastern bloc member states - such as Estonia, Latvia and Lithuania - warned they could be the next target of Russian aggression following Moscow's incursions into eastern Ukraine.
Estonian President said there should be a permanent Nato base in his country's territory.
Under the Nato treaty, the whole alliance would be obliged to defend any member state if they came under an attack.
Rockets, destroyed buildings and burned cars are among the signs of a fierce battle between the pro-Russian rebels and Ukrainian forces clearly visible on the streets of the eastern Ukraine's town of Ilovaysk, ITV News' Senior Foreign Editor John Angier reports.
The International Monetary Fund has warned that Ukraine might need as much as $19 billion (£11.5 billion) in additional loans if the fighting in east of the country continues into next year.
The IMF has already agreed to provide Ukraine with $17 billion (£10.3 billion) loan program.
Pro-Russian rebels in eastern Ukraine are now in control of the area around Donetsk, ITV News' Europe Editor James Mates reports.
Europeans should eat more fruit and vegetables to make up for Russian restrictions on food imports from Western countries, Germany's agriculture minister said.
"Eat! You should eat, I should eat, we should eat," the minister, Christian Schmidt, told German radio.
In a tit for tat move, Russia imposed one-year embargo on nearly all food imports from the EU, the US, Canada, Australia, Norway and Australia.
"You cannot lament the fact that there is lots of fruit and then not eat fruit, that much is obvious," Schmidt said in the interview with Deutschlandfunk.
The EU has introduced measures to help some European farmers affected by the ban.
The European Commission has suggested a new set of sanctions against Russia.
The bloc's leaders are negotiating the next round of sanctions this week.
Here is what some European countries proposed, according to Reuters news agency.
- Barring Russia from cultural and sports events
- Russian government-owned companies, not just banks, should be banned from borrowing money in the EU
- A list of goods completely banned from being exported to Russia should be expanded on goods that can have both military and civilian use. At the moment, only military goods are barred
- Expanding a ban on certain financial instruments sold by state-owned Russian banks in the EU
- Extending ban on selling advanced energy technologies to Russia
- Adding Russian Defence Minister Sergei Shoigu to the list of Russians barred from entering EU and freezing his EU assets
Estonia wants Nato to set up permanent bases on its territory to defend against Russia and ease fears that the Baltic state could be the next flashpoint after Ukraine, President Toomas Hendrik said.
Hendrik, visiting Oslo on the eve of a visit to Estonia by U.S. President Barack Obama in the run-up to a Nato summit in Wales, said "yes" when asked at a news conference if he wanted permanent Nato bases in Estonia.
"We should not have Nato with two-tier countries: with Nato permanent bases and without. This is a wrong signal to send to the potential aggressor," he said.