Policemen and medics remove debris as they search for victims at the site of a Saudi-led air strike on the police headquarters in Yemen's capital Sanaa. Reuters/Khaled Abdullah

At least 26 people have been killed and 15 others wounded in an air strike by the Saudi-led coalition on a police building in Yemen's capital Sanaa, security officials said.

The officials, who are loyal to anti-government Shiite rebels known as Houthis, said another 30 people are believed to be trapped under the debris of the badly damaged building.

Security forces swiftly sealed off the area as earth-moving equipment arrived to help with the search for bodies and survivors under the debris.

The officials initially announced that 20 people were killed, but later said that six bodies were unearthed from under the debris.

Police vehicles parked in the facility's courtyard were destroyed and nearby homes suffered some damage, they said.

The dead and wounded were policemen and Houthi rebels, they said.

The building was partially used as a gathering point for security forces and on occasion used by the Houthis as an assembly point for forces headed to deployment elsewhere in Yemen.

The air strike happened shortly before midnight on Sunday, according to the officials, who added that reporters were barred from approaching the facility.

The Saudi-led coalition began air strikes against the Houthis and their allies in March 2015, siding with the internationally recognised government.

Meanwhile, the Integrated Regional Information Networks (IRIN), a Nairobi-based humanitarian news agency, has announced the death of one of its contributors in Yemen.

In a statement, it said 35-year-old Almigdad Mohammed Ali Mojalli was killed just outside Sanaa on Sunday in an "apparent" air strike.

Mojalli also contributed from Yemen to Western media outlets, including Voice of America and the Daily Telegraph, said the statement.

PA Media