US Republican presidential nominee Donald Trump ratcheted up tensions in his party on Tuesday by denying two leading figures, House of Representatives Speaker Paul Ryan and Senator John McCain, support in their re-election bids. Trump told The Washington Post in an interview that he could endorse neither Ryan, the top US elected Republican, nor McCain, a US senator from Arizona and a former Republican presidential nominee, as they face challenges in their states' primary contests ahead of the Nov. 8 general election. Both Ryan and McCain had criticized Trump's feud with the family of Army Captain Humayun Khan, who died in the line of duty in Iraq in 2004 and was awarded the Bronze Star Medal for bravery after his death. The discord comes just two weeks after the Republican National Convention in Cleveland that formally nominated Trump for president. It is the latest rift in a party already frayed by internal dissent over its standard bearer, seen in stark relief at the convention where McCain was among high-level party members who essentially snubbed Trump by choosing not to attend. Mitt Romney, the 2012 Republican nominee, and former presidents George H.W. Bush and George W. Bush also did not attend the convention. Trump has had a running dispute with Khizr and Ghazala Khan since they took the stage at last week's Democratic convention to cite their son's sacrifice and criticize Trump's proposed ban on Muslims entering the United States. The uproar has led many Republicans to distance themselves from Trump and voice support for the Khan family. Trump, mirroring the language Ryan used about supporting the nominee before his eventual endorsement, told the newspaper he was "not quite there yet" on endorsing Ryan in next Tuesday's Wisconsin primary, and that he had "never been there" with McCain, who will be on the ballot in primary elections in Arizona later this month. McCain had a "very friendly" meeting with Trump's vice presidential running mate, Mike Pence, on Tuesday in Arizona, where Pence was visiting, a McCain spokeswoman said. Trump said Ryan had sought his endorsement, but that as of now he is only "giving it very serious consideration." Ryan's campaign office quickly responded that "neither Speaker Ryan nor anyone on his team has ever asked for Donald Trump's endorsement." "And we are confident in a victory next week regardless," campaign spokesman Zack Roday said in a statement. Meanwhile, In a searing denouncement, President Barack Obama castigated Donald Trump as "unfit" and "woefully unprepared" to serve in the White House. He challenged Republicans to withdraw their support for their party's nominee, declaring "There has to come a point at which you say ‘enough.'" While Obama has long been critical of Trump, his blistering condemnation on Tuesday was a notable escalation of his involvement in the presidential race. Obama questioned whether Trump would "observe basic decency" as president, argued he lacks elementary knowledge about domestic and international affairs and condemned his disparagement of an American Muslim couple whose son was killed while serving the US Army in Iraq. A chorus of Republicans has disavowed Trump's criticism of Khizr and Ghazala Khan and the Republican nominee's calls to temporarily ban Muslims from coming to the US. But Obama argued that isn't enough. "If you are repeatedly having to say, in very strong terms, that what he has said is unacceptable, why are you still endorsing him?" Obama asked during a White House news conference. "What does this say about your party that this is your standard-bearer?" No prominent Republican lawmaker responded to Obama's challenge.
