MOGADISHU, May 3 (Xinhua) -- The International Committee of the Red Cross (ICRC) on Thursday called for the safe release of its staff member who was abducted in the restive Somali capital Mogadishu on Wednesday evening.

Daniel O'Malley, ICRC's deputy head of delegation for Somalia, said armed men entered the agency's compound at around 8pm and abducted the German nurse.

"We are deeply concerned about the safety of our colleague. She is a nurse who was working every day to save lives and improve the health of some of Somalia's most vulnerable people," O'Malley said in a statement.

The charity said it is in contact with various authorities to try and secure her release, noting that it's not appropriate to provide any additional information at this stage.

"We are calling for her immediate and unconditional release," Crystal Wells, ICRC spokeswoman told Xinhua on Thursday.

Security forces sealed off the compound immediately after the abduction and have already started investigations into the incident in Wadajir district.

Sources said the private security guards who manned the compound when the incident took place were arrested.

Attacks against humanitarian workers operating in the Horn of Africa nation are common and have increased in the recent past in the country which has been torn asunder by factional fighting since 1991 but has recently made progress towards stability.

The latest abduction came a day after a Somali aid worker was shot dead by unknown gunmen in the main market in Mogadishu on Tuesday.

It also comes barely three months after a Ugandan working for UNICEF was killed by a former security guard in the organization's office the same area.

The Islamist group, al-Shabab which is fighting to topple the Western-backed government, has been targeting aid workers for political gain, sometimes demanding ransom in order to free the hostages.

The humanitarian community says the volatile security situation continues to impact on civilian lives and create a challenging environment for the delivery of humanitarian assistance.