Two fatal helicopter crashes in Afghanistan and large-scale bombings in Iraq have thrown into stark relief the risks for President Barack Obama in fulfilling his campaign pledge of shifting Washington’s resources from one conflict to the other.

A boy sits among Afghan elders during a meeting to discuss military action in their area
In the worst day for US casualties in Afghanistan for several years, 11 US ­soldiers and three Drug Enforcement Administration officials died in the two helicopter failures on Monday, one of which involved a mid-air collision and the other a crash following a firefight with insurgents.

The day before, up to 155 people were killed by twin bombings of government buildings in Baghdad, with possible consequences for US plans to reduce forces in Iraq. It was the second such bombing in two months.

Kenneth Pollack, director of the Saban centre at the Brookings Institution, said: “These events happening simultaneously demonstrates that the situation in Afghanistan is worsening while the situation in Iraq is not improving quickly enough.”

Military officials said that according to preliminary investigations neither of the helicopter crashes in Afghanistan was the result of enemy action.

Still, October is now set to be the fourth consecutive month in which more than 40 US military personnel have died in Afghanistan, underlining both the increased fighting since Mr Obama decided to raise US forces by 21,000 and the prospect of further casualties should he accede to his commander’s request for a further 40,000.

Mr Obama and his top officials continued meetings on Monday to decide on that request and overall strategy on Afghanistan, even as John Kerry, the influential senator, called for narrower war goals.

But the US is committed to a dramatic switch in resources. Admiral Mike Mullen, chairman of the US joint chiefs of staff, said last week: “We are shifting the main effort from Iraq to Afghanistan, literally.”

US forces in Iraq have already come down from 133,000 when Mr Obama took office to 120,000 today and are scheduled to fall to 50,000 by August 31 next year. Planning has started to shift the vast majority of 3.3m pieces of military equipment either back to the US or to Afghanistan.

The drawdown in Iraq is scheduled for March, after parliamentary elections that are supposed to take place in January. The date and nature of the elections are yet to be determined because of a deadlock over a new electoral law.

But US officials say that even if a law were not agreed, the elections can still take place – albeit at the end of January rather than midway through – and that the timing of the contest should not affect forces available for Afghanistan.

Mr Pollack added that the security challenge posed by the Baghdad bombings was much more significant than the electoral dispute as it could push Nouri al-Maliki, Iraq’s prime minister, to ask US forces to return to the country’s cities, after a pullout from urban centres in June. That in turn would have a significant impact on US troop strength in Iraq and the overall strain on the US military.

In the short term, US officials and some analysts say, the military has the capacity to meet demands for more troops in Afghanistan, principally by recourse to light infantry brigades not yet deployed.

Even if Mr Obama granted the 40,000 request in full, the extra troops would be deployed gradually because of logistic restraints .

Frederick Kagan at the American Enterprise Institute, said: “Any increase would be more of a trickle than a surge and would take place over the course of next year. There’s no way that we are going to throw 40,000 troops in there in three months.”

But over the longer term, the political and military risks of a large-scale switch to Iraq clearly complicate Mr Obama’s choice.

Mr Pollack suggested that if the situation in Iraq worsened Mr Obama could face a choice between Iraqi security and the promised drawdown – with all it implies for resources for Afghanistan. “That’s not a dilemma that the president wants to have,” he added.

In comments at a naval base in Florida on Monday Mr Obama himself highlighted his Afghan dilemma. “I will never rush the solemn decision of sending you into harm’s way; I won’t risk your lives unless it is absolutely necessary,” he told servicemen and women. But he added: “If it is necessary, we will back you up to the hilt.”