Baghdad ? Bombs ripped through apartment buildings and a market in mostly Shiite areas of Baghdad on Tuesday, killing 50 people in postelection bloodshed that threatens to rekindle sectarian warfare that nearly destroyed the country three years ago.

The attacks appeared to be an attempt by al-Qaida in Iraq or other extremists to exploit a power vacuum during what promises to be lengthy negotiations to form a new government. About 120 people have been killed in and around the capital over the past five days — some of the most brutal strikes on civilians in months.

For two terrifying hours on a warm, sunny Tuesday morning, at least seven bombs rocked a broad swath of Baghdad. In a new tactic, several bombs were planted inside empty apartments after renters offered high prices for the properties, the government said.

The explosions reduced one building to rubble, knocked out windows and doors and ripped off facades. People rushed to the blast sites, digging through the rubble with their hands to find loved ones.