Somalia's interim President Abdullahi Yusuf is being treated in a London hospital after he collapsed last week.
President Yusuf was treated for bronchitis last month
He was first taken to a hospital in Ethiopia on Friday before being rushed to London on Sunday.
A Somali diplomat said Mr Yusuf, 72, was in London for tests and a check-up. But opposition parties said he was critically ill.
The president was last month admitted to a Kenyan hospital, officially suffering from bronchitis.
He then underwent tests in London.
"He is back in London to receive part of the results of the medical tests he underwent and to undergo any new ones if necessary," Yusuf Mohamed Ismail, the Somali ambassador to the UN European office in Geneva, told Reuters news agency.
In the president's absence, Prime Minister Nur Hussein Hassan, who took office in November, has appointed 15 members of a cabinet to replace those he dismissed last month.
The ministers were sworn in on Saturday. Three positions are still to be filled.
Ethiopia helped Somalia's transitional government end the Union of Islamic Courts' (UIC) six-month rule over large parts of southern Somalia a year ago.
Since then the government has been battling insurgents in the capital, Mogadishu.
The UN says 60% of the residents of the capital, Mogadishu, have fled their homes because of fighting in recent months.
Somalia has not had a functioning national government since 1991.
Hassan Barise of the BBC's Somali Service says it had been feared the president's collapse would delay the cabinet appointments.
He says despite the setback to his health, no-one is expecting President Yusuf to step down.