By Nevzat Devranoglu and Ali Kucukgocmen
ANKARA (Reuters) -President Tayyip Erdogan said on Wednesday that Turkey's air operations against a Kurdish militia in northern Syria were only the beginning and it would launch a land operation when convenient after an escalation in retaliatory strikes.
He said Turkey was more determined than ever to secure its southern border with a "security corridor", while ensuring the territorial integrity of both Syria and Iraq, where it has also been conducting operations against Kurdish militants.
"We are continuing the air operation and will come down hard on the terrorists from land at the most convenient time for us," Erdogan told his AK Party's lawmakers in a speech in parliament.
"We have formed part of this corridor (and) will take care of it starting with places such as Tel Rifat, Manbij and Ain al-Arab (Kobani), which are the sources of trouble," he added.
Turkey and its Syrian rebel proxies took control of the border areas to the west and east of the Kobani region in previous military incursions.
Russia has asked Turkey to refrain from a full-scale ground offensive in Syria, senior Russian negotiator Alexander Lavrentyev said on Wednesday after a fresh round of talks about Syria with Turkish and Iranian delegations in Kazakhstan.
Meanwhile, the United States has conveyed serious concerns to Turkey, a NATO ally, about the impact of escalation on the goal of fighting Islamic State militants in Syria.
Turkey has previously launched military incursions in Syria against the Kurdish YPG militia, regarding it as a wing of the outlawed Kurdistan Workers Party (PKK), which Turkey, the United States and the European Union designate as a terrorist group.
Ankara launched air operations at the weekend in retaliation for an Istanbul bomb attack a week earlier that killed six people, and which it blamed on the YPG. Nobody has claimed responsibility and the PKK and YPG have denied involvement.
KOBANI SEEN AS TARGET
Turkish Defence Minister Hulusi Akar said the army had hit 471 targets in Syria and Iraq since the weekend. His ministry cited him as saying 254 militants had been "neutralised", a term generally used to be mean killed.
YPG-led Syrian Democratic Forces (SDF) commander Mazloum Abdi said in an interview with Al-Monitor news website that his home city of Kobani would be the "true target" of any ground offensive, being of strategic importance for Turkey in connecting areas in Syria that it already controls.
He criticised a "weak response" by Russia and Washington to the Turkish airstrikes.
The United States has allied with the SDF in the fight against IS in Syria, causing a deep rift with Turkey.
(Reporting by Nevzat Devranoglu, Ali Kucukgocmen and Huseyin Hayatsever, Tamara Vaal in Astana; Writing by Daren Butler; Editing by Jonathan Spicer, Nick Macfie, William Maclean, Alexandra Hudson)