WASHINGTON (AP) — Amid fresh concerns over the safety of American forces, President Barack Obama on Tuesday said the accidental burning of Qurans in Afghanistan and the retaliatory killings of U.S. troops gave new credence to the need to end the war.

“I think that it is an indication of the challenges in that environment, and it’s an indication that now is the time for us to transition,” Obama said during a White House news conference.

Obama announced no speeding up of the NATO-backed plan to end combat missions in Afghanistan at the end of 2014, saying “that continues to be the plan.” But he said the violence aimed at Americans in Afghanistan that followed the accidental burning of Qurans on a U.S. base was “unacceptable.”

Six Americans were killed in retaliatory violence. Obama offered his apologies to Afghan President Hamid Karzai, a move that was roundly criticized by his Republican presidential rivals as weak and unnecessary.

From Congress, Obama was getting tugged from another direction. A letter calling for Obama to accelerate the withdrawal of U.S. troops from Afghanistan had the backing of 23 senators, mostly Democrats but including two conservative Republicans, Sens. Mike Lee of Utah and Rand Paul of Kentucky.

Sen. Max Baucus, D-Mont., who circulated the letter with Sen. Jeff Merkley, D-Ore., said in a statement that there “something fundamentally wrong with spending $88 billion for national building in Afghanistan while we’re asking Americans to make tough cuts here at home.”

Foreign policy and domestic politics battled for top billing in Obama’s first White House news conference of the year, which coincided with Super Tuesday, the 10-state voting contest for Republican presidential hopefuls.

Obama insisted that diplomacy can still resolve the crisis over Iran’s possible pursuit of nuclear weapons, and he accused his Republican critics of “beating the drums of war.”

Obama said he emphasized that message in his private meetings with Israel’s Benjamin Netanyahu this week, and implied that Israeli pressure for urgent action was not supported by the facts, saying that a decision was not necessary within the next weeks or months.

Addressing another international crisis in Syria, Obama said the violence there was “heartbreaking” but he showed no new willingness for military involvement in that Mideast country.

Obama said unilateral military action by the United States against the government of Syrian President Bashar Assad would be a mistake. And he rejected a comparison to Libya, where the United States and allies did intervene last year, saying the situation in Syria is more complex. In Syria, Russia has blocked a U.N. Security Council resolution against Assad’s government, and Assad’s military is better equipped and more powerful than the Libyan force.

More than 7,500 people have been killed in Syria during the year-long government crackdown on the opposition.

Turning to domestic politics, Obama said higher gasoline prices as a result of Mideast worries would be bad for any president running for re-election, and he also said he was working to expand America’s energy base.

Obama also dismissed as laughable the suggestion by some Republican critics that he actually supports increased gas prices. No president facing re-election would want to see gas prices rise, he said, because of the hardship that would cause American families.

In the past month, gasoline prices have risen by more than 28 cents per gallon, making gasoline the most expensive ever for this time of year. On Tuesday, the nationwide average for regular unleaded slipped less than a penny to $3.764 per gallon, ending a string of price increases that began on Feb. 8.

Obama said he had asked his attorney general to examine whether speculation in the oil markets is driving up oil prices.

The president also made an election year appeal to women, a key voting bloc for Obama in the general election. Obama confidently asserted that Democrats would have a “better story” than Republicans to tell female voters November on everything from housing to education to contraception.

Obama’s campaign has been particularly pointed in his outreach to women on the issue of access to birth control. The president made a pointed entry in the debate last week when he called a Georgetown University Law School student who was criticized by radio commentator Rush Limbaugh because of her vocal support for his administration’s requirement of birth control insurance coverage.

Obama said he telephoned Sandra Fluke, who was labeled a “slut” by Limbaugh, because he doesn’t want people who speak their minds about policy issues to be discouraged or attacked.

Asked to comment on Limbaugh’s apology, Obama says he doesn’t know “what’s in Rush Limbaugh’s heart.”

Obama said the incident made him think of his two daughters and his hopes that they can engage in issues they care about in the future. He said he doesn’t want his daughters “attacked or called horrible names” for speaking their minds and being good citizens.

Copyright 2012 The Associated Press.