Somalia's allies expressed alarm over the intensifying row between the country's president and prime minister as heavily armed factions patrolled parts of Mogadishu.
Fears have been raised the political crisis could erupt into violence.
Soldiers loyal to the premier took up positions near the presidential palace, a day after President Mohamed Abdullahi Mohamed, better known as Farmajo, announced the suspension of Prime Minister Mohamed Hussein Roble, who accused him of an "attempted coup".
Relations between the pair have long been frosty, but the latest developments have sparked concerns for Somalia's stability as the country struggles to hold long-delayed elections and fight a jihadist insurgency.
On Tuesday, pro-Roble troops paraded the streets, fuelling fear among Mogadishu residents weary of armed confrontations.
Demonstrators from Somali anti-government opposition groups have previously burned photographs of the president. Source: AP
"They are not far away from the main security checkpoints of the presidential palace, they are armed with heavy machine guns and RPGs (rocket-propelled grenades)", Saido Mumin, a resident, told AFP.
Another local, Abdukadir Ahmed, said that although the situation appeared to be calm, he was "really worried" about the potential for violence.
International observers have urged both sides to resolve the festering dispute while some Somali traditional elders and politicians have also sought to calm tempers.
"Some politicians and elders (have) started going between the two sides to de-escalate the situation, but these efforts are yet to ... bring about a formal resolution", a source in the office of the president told AFP on condition of anonymity.
The Africa Bureau of the US State Department warned on Monday that Washington was "prepared to act against those who obstruct Somalia's path to peace".
"The attempted suspension of @MohamedHRoble is alarming & we support his efforts for rapid & credible elections. All parties must desist from escalatory actions & statements," it said on Twitter.
Mr Farmajo has accused Mr Roble of interfering with a probe into a land-grabbing case and withdrawn his mandate to organise elections.
Mr Roble in turn has accused Mr Farmajo of attempting to carry out "a coup against the government, the constitution, and the rules of the country" and sabotage the vote.
International observers and allies, including the African Union Mission in Somalia (AMISOM), the United States, the European Union, and the United Nations, released a statement late on Monday, expressing "deep concern" over the crisis.
"We call on Somalia's leaders to put the country's interests first, to de-escalate rising political tensions, and to refrain from provocation or use of force that could undermine peace and stability," the statement said.
"International partners have repeatedly expressed growing concern over procedural irregularities and delays in the Somali electoral process."
Analysts say the election impasse has distracted from Somalia's larger problems, most notably the Al-Shabaab insurgency.
The al-Qaeda allies were driven out of Mogadishu a decade ago but retain control of swathes of countryside and continue to stage deadly attacks in the capital and elsewhere.
