This article originally appeared on The Hill's Congress Blog. 

By Michael Boyce

BEIRUT - Lebanon is a country of tremendous complexity. But the country's mood today can probably be summed up in one word: tense. It may not seem that way to tourists in Beirut, where the mix of cosmopolitan nightlife and Mediterranean views is enough to keep any visitor occupied. But residents say that the bars are not as busy as they once were. Soldiers are patrolling streets where they would have been absent a few months before. More and more people are arming themselves, and have been using those arms in clashes in Beirut and Tripoli.

Some claim that this does not represent a trend: "This is Lebanon," they say, "these things just happen sometimes." But many more are genuinely worried - and their worries are rooted across the border in Syria. Looking at their giant neighbor, they see horrendous violence that shows no signs of stopping, a failing UN monitoring mission, and rising militancy on both sides. They also see a country on which they have depended - economically, politically, and militarily - for decades, and whose problems could very quickly become their own.

Average Lebanese are tense, and so is their government. With its officially neutral stance on Syria, the government has walked a tightrope for months to distance itself from the conflict between Syrian President Bashar al-Assad and opposition groups. But the most tense of all may be the Syrian refugees themselves, of which there are now at least 26,000 in Lebanon alone. Many have lost loved ones in the conflict, been wounded or maimed, or suffered serious psychological trauma. And while some have come forward to speak about their problems and seek help, others still live in fear. They worry that among their number may be Syrian spies, and that information they give to aid groups could all too easily be leaked to Assad sympathizers. (One man we visited refused even to have his voice recorded for fear he might be identified.) This means that many Syrians may be living underground - beyond the reach of international and local aid providers.

These refugees' fears are not mere paranoia. In the border areas where many of them live, the line between Syria and Lebanon is not easily drawn. Day workers, smugglers, and perhaps things more sinister, go back and forth between the two countries daily. It's not inconceivable that if a man was identified as living in Lebanon one day, his home in Syria could be broken into the next. But this fear is having an impact on assistance. Aid groups say that they are meeting most refugees' basic needs - like food and shelter - but one Syrian we met said that many of his compatriots are being missed. He claimed, for example, that he had seen Syrian refugees sleeping in open fields at night, with cardboard boxes for blankets. Finding a way to access these people quickly and deliver help, without putting them in danger, is critical.

The tension hanging about Lebanon these days is unlikely to abate soon, and could explode into open hostility at any time. If that were to happen, delivering aid to Syrian refugees in Lebanon - and getting political support for that aid - could become even more difficult. Aid providers cannot prevent those hostilities from breaking out, but they can make sure that those Syrian refugees who now live in fear don't also live in deprivation.