Turkey President Recep Tayyip Erdogan said Sunday that his country would oppose any U.S. arms transfers to Kurdish forces that are fighting the Islamic State militants.

Turkey believes that PYD, the main group fighting against the Islamic State, is "no different" than PKK, which has fought against Turkey for 30 years and is considered a terrorist organization by the U.S. and NATO.

U.S. officials declared recently that they had not ruled out arms transfers to the Kurdish fighters in the near future. They also said that the U.S. was involved in intelligence sharing with Kurdish fighters.

"The PYD is for us, equal to the PKK. It is a terror organization," Erdogan told a group of reporters on his return from a visit to Afghanistan.

"It would be wrong for the United States - with whom we are friends and allies in NATO - to talk openly and to expect us to say 'yes' to such a support to a terrorist organization," Erdogan said, reports the Associated Press.

President Obama spoke with Erdogan Saturday regarding the state of affairs in the Syrian border town of Kobani and measures to be taken to thwart the Islamic State progress, the White House said.

Turkey recently consented to train and arm moderate Syrian rebels fighting against Syrian President Assad. It also has offered refuge to around 200,000 Syrians who escaped from Kobani fearing the Islamic State.

Meanwhile, fierce fighting is going on between the Islamic State militants and the Kurdish fighters in the Syrian border town of Kobani, reports Reuters.

Britain-based monitoring group the Syrian Observatory for Human Rights said Islamic State militants fired 44 mortars at Kurdish areas of Kobani on Saturday and four more on Sunday. Some of the shells fell inside neighboring Turkey also, it said.

The Observatory said that 70 Islamic State fighters were killed in the past two days, citing sources at a hospital in the town of Tel Abyab near Kobani.