While the world focuses on the flood-ravaged Indus River valley, a quiet geopolitical crisis is unfolding in the Himalayan borderlands of northern Pakistan, where Islamabad is handing over de facto control of the strategic Gilgit-Baltistan region in the northwest corner of disputed Kashmir to China.

The entire Pakistan-occupied western portion of Kashmir stretching from Gilgit in the north to Azad (Free) Kashmir in the south is closed to the world, in contrast to the media access that India permits in the eastern part, where it is combating a Pakistan-backed insurgency. But reports from a variety of foreign intelligence sources, Pakistani journalists and Pakistani human rights workers reveal two important new developments in Gilgit-Baltistan: a simmering rebellion against Pakistani rule and the influx of an estimated 7,000 to 11,000 soldiers of the People’s Liberation Army.

China wants a grip on the region to assure unfettered road and rail access to the Gulf through Pakistan. It takes 16 to 25 days for Chinese oil tankers to reach the Gulf. When high-speed rail and road links through Gilgit and Baltistan are completed, China will be able to transport cargo from Eastern China to the new Chinese-built Pakistani naval bases at Gwadar, Pasni and Ormara, just east of the Gulf, within 48 hours.

Many of the P.L.A. soldiers entering Gilgit-Baltistan are expected to work on the railroad. Some are extending the Karakoram Highway, built to link China’s Sinkiang Province with Pakistan. Others are working on dams, expressways and other projects.