ISTANBUL (AFP) - Turkish Prime Minister Recep Tayyip Erdogan warned the army Friday that no one is above the law as a probe into an alleged 2003 coup plan to oust the government widened with the detention of 18 more soldiers, media reports said. Those who make plans behind closed doors to crush the peoples will must see that from now on they will face justice, Erdogan said in Ankara. No one is above the law, no one has impunity. The NTV news channel said 18 soldiers, one of them retired, were rounded up in 13 provinces in a second wave of arrests over the purported plot to foment unrest and justify a military takeover against the Islamist-rooted government. One of the suspects was the head of the paramilitary force in the central Konya province, the report said. Erdogan dismissed accusations that his party was trying to discredit the army to obtain a free hand in realising a secret agenda, hailing the probe as a sign of improving democracy.What is happening today is normalisation... These are the footsteps of an advanced democracy, he said. In Istanbul, prosecutors were questioning several suspects, among them retired four-star general Cetin Dogan, who allegedly spearheaded the coup plot, Anatolia news agency said. Earlier, a court jailed 11 people pending trial, bringing the total number of those charged to 31, including both serving and retired soldiers. The three most senior figures questioned so far - ex-navy chief Ozden Ornek, former air force commander Ibrahim Firtina and the former number two of the general staff, Ergin Saygun - were released late Thursday. However, the prosecutor in charge said the investigation was continuing, raising the possibility that the trio may still face trial.