Bissau - Four officers suspected of participating in a failed military coup against Gambia's strongman President Yahya Jammeh have taken refuge in Guinea-Bissau, a military source in the west African country told AFP on Thursday.They "arrived on Wednesday evening in Bissau and turned themselves in to the [military] authorities", the source in Bissau told AFP.The source, who asked not to be identified, did not explain how the fugitives had reached Guinea-Bissau, which is to the south of Gambia, but separated by Senegal.A group of heavily armed men led by an army deserter attacked the presidential palace in the Gambian capital Banjul before dawn on Tuesday, but were repelled by forces loyal to Jammeh, who has ruled for 20 years.Jammeh returned overnight on Wednesday from Dubai where he was on a private visit at the time of the putsch attempt.Three suspects including the alleged ringleader identified as Lamin Sanneh were killed, according to a military officer.According to a diplomatic source in Banjul, Jammeh appears to be preparing a purge of opponents, with "accusations flying".Jammeh on Thursday blamed unidentified foreign dissidents and "terrorists" for an assault on his presidential palace and said that the army remains loyal."It is an attack by dissidents based in the US, Germany and UK," Jammeh said in a televised address. "This was not a coup. This was an attack by a terrorist group backed by some powers that I would not name.""The names of military and civilian individuals are starting to be put on the table" at the feared National Intelligence Agency," the source said. "I'm afraid that innocent people are going to be caught up through denunciations."