UPDATE | Sessions out as US attorney general

WASHINGTON (AP) — Attorney General Jeff Sessions was pushed out today as the country's chief law-enforcement officer after enduring more than a year of blistering and personal attacks from President Donald Trump over his recusal from the Russia investigation.

Sessions told the president in a one-page letter that he was submitting his resignation "at your request."

Trump announced in a tweet that he was naming Sessions' chief of staff Matthew Whitaker, a former United States attorney from Iowa, as acting attorney general.

The resignation was the culmination of a toxic relationship that frayed just weeks into the attorney general's tumultuous tenure, when he stepped aside from the investigation into potential coordination between the president's Republican campaign and Russia.

Trump blamed the decision for opening the door to the appointment of special counsel Robert Mueller, who took over the Russia investigation and began examining whether Trump's hectoring of Sessions was part of a broader effort to obstruct justice and stymie the probe.

The implications for Mueller's investigation were not immediately clear. The Justice Department did not announce a departure for Deputy Attorney General Rod Rosenstein, who appointed Mueller more than a year and a half ago and has closely overseen his work since then.

The relentless attacks on Sessions came even though the Alabama Republican was the first U.S. senator to endorse Trump and despite the fact that his crime-fighting agenda and priorities – particularly his hawkish immigration enforcement policies – largely mirrored the president's.

But the relationship was irreparably damaged in March 2017 when Sessions, acknowledging previously undisclosed meetings with the Russian ambassador and citing his work as a campaign aide, recused himself from the Russia investigation.

The decision infuriated Trump, who repeatedly lamented that he would have never selected Sessions if he had known the attorney general would recuse. The recusal left the investigation in the hands of Rosenstein, who appointed Mueller as special counsel two months later after Trump fired then-FBI Director James Comey.

The rift lingered for the duration of Sessions' tenure, and the attorney general, despite praising the president's agenda and hewing to his priorities, never managed to return to Trump's good graces.

The deteriorating relationship became a soap opera stalemate for the administration. Trump belittled Sessions but, perhaps following the advice of aides, held off on firing him. The attorney general, for his part, proved determined to remain in the position until dismissed. A logjam broke when Republican senators who had publicly backed Sessions began signaling a willingness to consider a new attorney general.