DIYARBAKIR, Turkey — Just when it seemed Turkey was getting serious about the fight against IS, it has turned its military focus to pounding its old foe: the Kurdish rebels.

In Turkey’s Kurdish heartland, the government’s renewed military onslaught against the rebels has left many people crying treachery — with suspicions rife that Turkey used a brief offensive against IS as a cover to launch a broad attack against the Kurdistan Workers Party, or PKK. Many Kurds also are venting frustration against the United States, accusing Washington of turning a blind eye to Turkish attacks on the Kurds in exchange for logistical support on IS.

“We are used to this. Kurds have witnessed betrayal for centuries” said Axin Bro, a musician. “National powers use us for their own ends.”

The US had welcomed Turkey’s air assault last week on the Islamic State group, along with its decision to open air bases for American sorties, as a sign that Turkey had dropped its reluctance to fight the extremist group. Since then, Turkish jets taking off from this city in Kurdish-dominated lands have been hitting PKK targets in northern Iraq and southeastern Turkey, as the militant group has targeted military and police in Turkey.

Turkish jets again pounded PKK targets in northern Iraq in an operation Thursday that lasted two-and-a-half hours, a government official said. He said the latest airstrikes were in retaliation for an attack on troops stationed near the border with Iraq earlier in the day that killed three soldiers. He spoke on condition of anonymity in line with government rules requiring prior authorization to speak to journalists.

The US has said Turkey has a right to defend itself against the PKK, which Washington, like Turkey, considers a terrorist group. The PKK is affiliated with, but separate from, Syrian Kurdish fighters allied with the United States in its fight against the Islamic State group. Turkish officials say the Syrian Kurdish group is not a target of Turkey’s operations.

Of the 1,300 people the government rounded up in a nationwide anti-terror sweep, the overwhelming number have been Kurdish. That may reflect the PKK’s greater presence in Turkish society, but Kurdish politicians charge that the government’s objective is to curb the rising political power of the Kurds.

The mayor of Diyarbakir said distrust is growing toward both the government and the US.

“People here see that there have been several weak operations against IS while there have been repeated operations against Kurds both politically and militarily,” Gultan Kisanak said in an interview.

She said many constituents are asking whether there was a tacit deal between Turkey and the US — for the US to look the other way on Kurdish operations in exchange for access to Turkish air bases. The White House has denied such claims.

The Turkish government has cast the simultaneous moves against IS and the PKK, as well as the arrest of members of a leftist group, as decisive steps to protect the public and Turkish democracy.

On Thursday, Prime Minister Ahmet Davutoglu said that the spike of violence by the PKK had forced Turkey to act against the Kurds, just as it was considering what to do about the apparent IS bombing last week near the border with Syria, which killed 32 people.

“While we were deciding on measures (after the suicide bombing), this time the PKK came into play,” said Davutoglu.

On Wednesday, Deputy Prime Minister Bulent Arinc gave a breakdown of the terror suspects rounded up in the nationwide police operation, saying that of the 1,300 detained, only 137 were suspected of links to IS. Some 31 have been charged so far, while 18 were released. In contrast, police detained as many as 847 PKK suspects. A total of 142 have been charged so far, while 120 were released.

All 15 IS suspects, including 11 foreign nationals, detained in raids at a low-income Ankara neighborhood this week were released, the state-run Anadolu Agency reported. The Haci Bayram district was the focus of media attention last year because some Turkish IS recruits came from the neighborhood.

“If the aim, as stated by the government, was to clear the border of the IS threat, the operation against IS in Syria appears to be weak and ineffective,” said Serkan Demirtas, columnist for Hurriyet Daily News. “We can see that the real focus is against the PKK.

“A small proportion of those detained are IS members,” Demirtas said. “We don’t know how many of them are effective operatives.”

Kurdish activists and government critics believe the government’s crackdown on the PKK is a tactic aimed at strengthening the ruling party ahead of possible new elections in November. Davutoglu’s Justice and Development party lost its parliamentary majority in the June 7 elections after Kisanak’s pro-Kurdish HDP party made huge gains, and passed a 10 percent minimum vote threshold to be represented in parliament. The ruling party has until Aug. 24 to form a government before new elections are called.

On Thursday, a prosecutor launched an investigation into the HDP’s leader, Selahattin Demirtas, over alleged attempts to disrupt peace and public order by calling for protests in October that resulted in violence, the Anadolu Agency reported. The move came two days after President Recep Tayyip Erdogan said Kurdish politicians should be prosecuted for links to terror groups.

“Turkey appears to be engaged in a strategy of hitting two birds with one stone by giving the impression of fighting ISIL while simultaneously starting operations against the PKK,” wrote Lale Kemal, a columnist for Zaman newspaper, using one of the acronyms of the Islamic State group.

“The plan appears to be to ensure that conservative Kurdish votes return to the AKP in early elections,” Kemal wrote.

On Thursday, the military said the PKK attacked soldiers protecting a military convoy in Sirnak province, near the border with Iraq. Three soldiers, including an officer, died. The military responded with a counter-offensive that killed one PKK rebel.

In an earlier assault, Kurdish rebels opened fire late Wednesday on a tea house in the mainly Kurdish city of Diyarbakir, killing a police officer and a civilian. Kurdish rebel attacks have claimed the lives of four policemen, eight soldiers and one civilian in the past two weeks, according to count by the Associated Press.