Syria crisis: US admits arming rebels is 'an option' The US defence secretary, Chuck Hagel has said that the Obama administration is reviewing whether to arm the rebels in Syria, becoming the first senior US official to acknowledge the possibility in public. During a Pentagon press conference with his British counterpart, Philip Hammond, Hagel said: Arming the rebels - that's an option. You look at and rethink all options. It doesn't mean you do or you will ... It doesn't mean that the president has decided on anything. Speaking later in Mexico, President Barack Obama confirmed his administration was examining all options. As debate continues over "red lines" and possible intervention, western intelligence agencies fear they can no longer prove for certain whether the Syrian government was responsible for alleged chemical weapon attacks, because initial samples and evidence trails have degraded over time. Hammond revealed the shortcomings in recent reliance on soil and blood samples ahead of his talks with Hagel. He said: The confidence that we are seeking degrades over time, and in order to have a properly measured chain of custody we would need to obtain samples after an[other] incident. If chemical weapons use continues, albeit on a small scale, then I am confident that we can detect further use. He later told BBC Newsnight the government would need incontrovertible" evidence of the use of chemical weapons if they were to be part of an international response, given the experience with discredited evidence in relation to the Iraq war. Journalists in Syria have been deliberately targeted by both sides in the conflict, Amnesty International says in a new report. It says at least 36 journalists have been killed in targeted attacks and the country is now the most dangerous in the world for journalists. The report details dozens of cases of journalists and media workers attacked or detained since the 2011 uprising began in an attempt to prevent them from reporting on the unfolding situation in Syria, including their reports on human rights abuses. Amnesty says it has recorded at least 17 incidents where armed opposition groups have deliberately targeted journalists and media workers - including deliberate attacks on buildings where they work - because they've been perceived as allied to the Syrian authorities or have produced pro-government reports. Ann Harrison, Amnesty International Middle East and North Africa deputy director, said: Deliberate attacks on civilians, including journalists, amount to war crimes for which the perpetrators must be brought to justice. We have once again documented how all sides in this conflict are violating the laws of war, although the scale of abuse by government forces remains much greater. Government forces and militia loyal to President Bashar al-Assad may have killed up to 100 people in the coastal village of Baida, activists have claimed. The British-based Syrian Observatory for Human Rights says at least 50 people were killed, including women and children, by summary execution, according to testimonies. Some were stabbed and some were burned, according to the reports. which the Observatory said it could not verify because the village has been locked down by regime troops. Lakhdar Brahimi, the UN-Arab League envoy for Syria, has informed senior UN diplomats that he intends to resign in the coming weeks, marking the end of another doomed UN diplomatic effort to end the conflict, the Washington Post reports, citing UN diplomats. The United States has sought to persuade Brahimi to put off his plans to step down until after US secretary of state John Kerry concludes a 7-8 May visit to Moscow for meetings on Syria and other matters with Russian Foreign Minister Sergei Lavrov, it says.