European Parliament Vice-President Eva Kaili was detained in Brussels on Friday in connection with an ongoing corruption investigation involving the Qatari government, AFP reported.

In addition, four other people were detained in this case, including the partner of the MEP, the agency added.

Quoting an anonymous source, AFP said police had detained Kaili for questioning.

Kaili is a MEP of the Progressive Alliance of Socialists and Democrats. The Greek daily "Kathimerini" reported that in connection with the ongoing investigation, the MEP was expelled from the Greek socialist party PASOK, to which she belonged.

Earlier on Friday, the Belgian prosecutor's office said it had launched an investigation into possible corruption linked to an unnamed Gulf state in which assistants and officials of the European Parliament are suspected. The media reported that this country was Qatar.