Russian and US : Rivals fear Syria clash if jets meet -

Moscow says it will work to avert potential mishaps between Russian and US pilots flying missions over Syria, Pentagon officials say.
As tensions heightened, US and Russian officials held discussions last week at Russia's request on establishing measures to avoid accidents so warplanes flying over Syria would not be in the same place at the same time.
The so-called "deconfliction" talks came after Russia began bombing in support of Syrian President Bashar al-Assad against Isis (Islamic State) and other rebel groups. But despite Russian violations of Turkish airspace since then, Moscow has not joined further talks, frustrating US military officials who had made repeated overtures.
US Defence Secretary Ashton Carter has spoken repeatedly in recent days about Russia's "irresponsible and unprofessional" moves in Syria. Moscow yesterday seemed to respond to those remarks. A senior defence official said Moscow had indicated it was open "in principle" to carrying out pledges made during the first round of talks.

Officials have said these commitments could include undertakings on which language Russian and American pilots will use for communication, the choice of radio frequency for distress calls, and the altitude at which warplanes will operate.
"We look forward to the formal response from the Russians and learning the details. We stand ready to meet again to continue our earlier discussion as soon as possible," Pentagon press secretary Peter Cook said.
Turkey says Russian fighter jets violated its airspace near the Syrian border on Sunday and Monday, further heightening tensions. Yesterday, it said eight Turkish F-16 jets carrying out reconnaissance flights over the Turkish-Syrian border a day earlier were held on radar lock by an unidentified MiG-29.
Radar lock enables a warplane's missile systems to automatically follow a target.
Carter said violations of Turkish airspace would "cause us further to strengthen our posture with respect to Russia" although he did not elaborate.
The Pentagon has repeatedly stressed that Russia's involvement in Syria would not alter continued air strikes against Isis jihadists there and in Iraq as part of a coalition of more than 60 nations.
Russia was forced into vehement denials that it was sending ground troops into battle in Syria, as uncertainty about how far it would push its intervention in the conflict lingered. Officials in Moscow dismissed reports, some from the Pentagon, of a build-up of artillery and multiple rocket launch systems as "unfounded.".
Meanwhile, AP reported yesterday that Eastern European authorities working with the FBI have interrupted four attempts in the past five years by gangs with suspected Russian connections to sell radioactive material to Middle Eastern extremists.
The latest known case came in February this year, when a smuggler offered a huge cache of deadly caesium - enough to contaminate several city blocks - and specifically sought a buyer from Isis.
Criminal organisations, some with ties to the Russian KGB's successor agency FSB, are driving a thriving black market in nuclear materials in the tiny and impoverished Eastern European country of Moldova, investigators say.
The successful busts, however, were undercut by striking shortcomings: kingpins got away, and those arrested evaded long prison sentences, sometimes quickly returning to nuclear smuggling, AP found.