Gunmen abducted a Westerner identified by a police source as a British oil worker in Sanaa on Monday, hours after three explosions shook the Yemeni capital, underscoring the transitional government's feeble grip on security.
The kidnapping followed that of a German by Yemeni tribesmen who said on Sunday they had seized him two days earlier to press the authorities to free jailed relatives.
A police source said two roadside bombs exploded near the Defence Ministry and Central Bank on Sunday night, while a mortar bomb landed in a district that houses the French embassy and the home of former President Ali Abdullah Saleh.
Four people were wounded in the mortar blast, which damaged three buildings and destroyed two cars, witnesses said.
One resident reported hearing gunfire after the explosions, but details were sketchy. In December, a suicide bomb and gun attack near the Defense Ministry killed 52 people.
Yemen, which neighbors oil giant Saudi Arabia and is home to an ambitious Al Qaeda offshoot, has long wrestled with instability, internal conflicts and poor governance.
Mass protests in 2011 eventually forced Saleh to end his more than three decades in power, but a political transition process has yet to calm a rebellion by Shia Muslims in the north and a secessionist movement in the south.
The Shia Houthi rebels who had carved out a northern fiefdom before Saleh's fall have clashed in recent months with hardline Sunni Muslim Salafis and Hashid tribal rivals.
Elsewhere, attacks blamed on Al Qaeda-linked militants have grown bolder, raising fears of a total security breakdown in Yemen, a nation mired in corruption that has aggravated poverty.
In Monday's kidnapping, four armed men forced the Westerner out of his car and into a waiting vehicle in Sanaa's upscale Hadda district, witnesses said. A police source said a report of the abduction identified the victim as a Briton. The source said the man worked for an oil services company.
The British embassy in Sanaa and the Foreign Office in London had no immediate comment.
It was not immediately clear if Islamist militants or tribesmen, who often use foreign hostages as bargaining chips to pursue demands against the government, were behind the attack.
Efforts to stabilize Yemen hang on the post-Saleh transition and a national reconciliation conference that ended last month.
Political factions have extended interim President Abd-Rabbu Mansour Hadi's term by another year to give him more time to turn Yemen into a federal state as agreed at the reconciliation talks to try to accommodate southern demands for more autonomy.
Hadi will also oversee the drafting of a new constitution that will form the basis of elections slated for next year.
(Additional reporting by Belinda Goldsmith in London; Writing by Yara Bayoumy and Amena Bakr, editing by Sami Aboudi and Alistair Lyon)