Two more suspects have been arrested in connection with last month's alleged plot to blow up trains in Germany, officials have said.
German police released security camera footage last week
One man was held in Germany, while another one was picked up in Lebanon, they said.
Altogether, four people have now been detained over the past seven days.
Two bombs were found on trains in the cities of Dortmund and Koblenz in July. The devices - left in identical suitcases - failed to go off.
Police said the bombers had intended to kill large numbers of people.
Security has since been stepped up at German airports and the rail authorities have announced they are installing more closed circuit TV cameras at stations.
German prosecutors said on Friday that one man was arrested in the southern German city of Konstanz on suspicion of belonging to a terrorist organisation.
They did not reveal his identity but said he was an associate of Lebanese student Youssef Mohammed el-Hajdib, who was arrested in the northern city of Kiel on Saturday.
In Lebanon, officials said a 24-year-old man was detained.
They said they acted following the questioning of another suspect, Jihad Hamad, who turned himself in to police in Lebanon's northern city of Tripoli on Thursday.
The arrests follow the release of closed-circuit TV footage of two male suspects by police last week.
In the video, the two suspects - dark-haired young men - are seen wheeling suitcases at Cologne station.
Investigators first thought the bombs were part of a blackmail attempt but they now believe the incident was the work of a terrorist group based in Germany.
A note written in Arabic, a telephone number in Lebanon, and packets of starch with labels in Arabic and English were found alongside the devices.
The identical suitcase bombs were fitted with timers set to go off 10 minutes before the trains arrived in Dortmund and Koblenz.
Police think they failed to detonate because of a construction flaw.