State of Siege — Eric Ambler

All in all Steve Fraser had enjoyed his three-year stint in the former Dutch Southeast Asian colony of Sunda, and he'd been well compensated. But now he was looking forward to a last weekend in the capital before heading home. But Sunda was newly independent, and not entirely stable. An opposition faction with fundamentalist Islamic leanings was set on overthrowing the provisional government. And instead of enjoying a sybaritic weekend with the Eurasian beauty Rosalie, Fraser finds himself trapped with her by a fanatical group who've taken over the country's radio station and made their headquarters in his friend Jebb's apartment. As the government launches a counterattack, the couple's survival depends on their ability to dodge bullets and the shifting loyalties of the coup's lieutenants.