A senior member of the Labor Party said Thursday the Bush administration was intervening in internal Israeli politics and promoting Kadima's Ehud Olmert for prime minister. Yitzhak Herzog, a former housing minister and current lawmaker, said the White House had been firmly behind Prime Minister Ariel Sharon, who suffered a massive stroke last week, and was now shifting it's support to his presumed successor Olmert in March 28 elections. Herzog cited reports that Olmert would soon be invited to the White House as evidence. "Aside from saying 'Go vote Sharon,' they did everything else," he said. "It is not proper and not appropriate, it is a crossing of red lines. I suggest to our friends in the United States to understand that we are in an election campaign and not to interfere in the election process in Israel and to act carefully in this time." Earlier Thursday, US President George W. Bush called Olmert, speaking with the acting Israeli prime minister for the first time since Prime Minister Ariel Sharon suffered a massive stroke last week, according to a statement from Olmert's office. Bush expressed concern for Sharon, who remained unconscious in critical, but stable condition. Sharon and Bush formed a strong relationship over the past five years. "I wanted to tell you that our hearts are with Ariel Sharon, his family, his friends and all the people of Israel," Bush told Olmert, according to the statement. "We know this is a difficult time for you, and whatever I can do to help I will." Bush also said that he would continue to implement the joint vision that he and Sharon had for promoting Middle East peace. He asked Olmert to tell Sharon's sons, Omri and Gilad, that Bush admires their father and wishes him the best, according to the statement. Bush also said that Hamas, which is running in January 25 parliamentary elections, must change its approach to Israel and recognize the Jewish state's right to exist, the statement said. Olmert told Bush that he admired his perseverance in fighting terror, according to the statement. Israeli officials on Thursday said Olmert may soon visit the White House, though the statement did not address the issue.