Yemen is battling to control an al-Qaeda movement estimated to have hundreds of fighters in the country, as well as so-called Houthi rebel fighters in the north of the country and a secessionist movement in the south.
Raid on al-Qaeda
At least two suspected al-Qaeda members were killed during a raid near Sanaa on Monday.
Officials said up to three other suspects had been wounded during the operation in the Arhab district, around 30km northeast of the capital.
Security officials told The Associated Press news agency the raid was not connected to the threats that prompted the US and UK embassy closures.
Hillary Clinton, the US secretary of state, said on Monday that a decision on reopening the US embassy would be taken "as conditions permit".
"We see global implications from the war in Yemen and the ongoing efforts by al Qaeda in Yemen to use it as a base for terrorist attacks far beyond the region," she said after meeting the visiting prime minister of Qatar.
The French embassy was also shut to the public on Monday, while the Japanese mission suspended consular activities as Yemeni authorities increased security in the city.
John Brennan, the US president's assistant for homeland security and counterterrorism, warned on Sunday that "there are indications that al-Qaeda is planning an attack against a target in Sanaa".
Over the weekend, Barack Obama, the US president, accused Al-Qaeda in the Arabian Peninsulaof arming and training a Nigerian man accused of trying to blow up a US airliner bound for the city of Detroit on Christmas Day.
The Yemen-based group, which claims to be affiliated with Osama bin Laden's organisation, had earlier claimed responsibility for the failed attack and called for strikes on embassies in Yemen.
Al-Qaeda in the Arabian Peninsula said that the failed attack was in response to a series of raids in western Yemen, which the groups says were carried out by US warplanes. Washington and Sanna have denied the claims.
The intensification of security efforts in Sanaa comes just days after the British government announced plans to join the United States in funding an "anti-terrorist" force in Yemen.
Gordon Brown, the British prime minister, has said he will hold a meeting in London on January 28 to discuss how to counter radicalisation in Yemen.
Al-Qirbi told Al Jazeera that the country needed development aid to improve social conditions in the country.
"Economic growth is a necessity for Yemen because one of the main challenges facing Yemen is to improve the standards of living, create jobs and fight poverty because these are the elements that contribute to extremism in Yemen," he said.
"Our first priority is development assistance and then we need also assistance to build and expand our counter-terrorism units"
Abu Baker al-Qirbi,
Yemeni foreign minister
"Our first priority is development assistance and then we need also assistance to build and expand our counter-terrorism units, equip them with all the logistic support they need.
"I know the Americans have committed more money for our counter-terrorism units and that is one area we need support in."
Hillary Mann-Leverett, a former US diplomat who worked at the national security council, told Al Jazeera that Yemen had long been a troubled state plagued by poverty and violence.
"The most important thing here for geopolitics globally and within the region, is that Yemen has been a fractured, desperately poor and deeply fractitious country that all the countries in the region and the superpowers have used as a battleground," she said.
But Mann-Leverett also said that the Obama administration's policies towards the region were partially to blame for threats against Washington and its allies.
"We have given the Saudis a green light to militarily intervene in Yemen and to characterise what is happening in Yemen as a Sunni-Shia war [with] the Saudis there to defend the Sunnis against craven Shia," she said.
"We're paying the price today of outsourcing our policy to the Saudis."