British Foreign Secretary William Hague greets U.S. Secretary of State John Kerry ahead of a meeting in the Foreign and Commonwealth Office in central London on Wednesday. (Ben Stansall/AP)

President Obama is moving toward final approval of battlefield support for Syria’s military opposition, including nonlethal items such as body armor and night-vision goggles, U.S. officials said Wednesday.

The development comes as the State Department has pushed the White House to join allies such as Britain and France, which have said that they will expand their supplies to the Syrian rebels.

“The president has directed his national security team to identify additional measures so that we can increase assistance” and coordinate with other countries, a senior administration official said. A decision is due “in the coming weeks,” the official said. “There are a good number of details that still need to be worked out.”

Secretary of State John F. Kerry, in London for a meeting with the Group of Eight foreign ministers, heard pleas from the rebels for more aid and weapons as the humanitarian crisis and death toll escalate in Syria.

Kerry, British Foreign Secretary William Hague and others who conferred with the Syrian opposition group agreed to meet again in Turkey on April 20 to discuss further assistance to the outgunned rebels fighting to oust Syrian President Bashar al-Assad. The two-year-old civil war has left more than 70,000 dead and created more than 1 million refugees, according to the United Nations.

Kerry said this week that the Syrian stalemate had left “no choice” but to increase outside pressure on Assad. The secretary provided no details, saying that an announcement would come from the White House.

Administration officials, speaking on the condition of anonymity to discuss closed-door meetings, said they did not believe additional nonlethal support, beyond already announced military meals and medical aid, would significantly alter the balance of the war. At the same time, there is concern that ratcheting up non-weapons support would increase demands to provide lethal aid, which Washington and the Europeans have refused.

But officials acknowledged that the United States has a credibility problem with the opposition that the provision of body armor and other battlefield assistance might help with.

The Cairo-based Syrian opposition figures came to London at Hague’s invitation, during a G-8 session intended to widen international contact with potential Syrian leaders apart from Mouaz al-Khatib, chairman of the U.S.-backed Syrian Opposition Coalition.

Amid disarray among opposition leaders, Khatib has resigned his position but said he will remain on the job until next month.

Kerry and Hague met with Ghassan Hitto, the prime minister of the temporary Syrian government-in-exile.

Hitto’s appointment has been a source of dissension within the opposition and among its outside backers. Saudi Arabia and Qatar, which back and supply arms to different factions of the opposition military, have told U.S. officials that Hitto is too tied to the Syrian Muslim Brotherhood, a group that they oppose but that Turkey and other countries in the neighborhood support.

A second senior administration official said that the United States is satisfied with Hitto’s performance and that its message to the political arm of the opposition is, “We don’t care what your personal relationships are. Talk to each other . . . and don’t complain about each other in public.”

In a statement after the meeting with Hague, coalition vice presidents George Sabra and Suheir al-Atassi said they “again underlined our commitment to combating extremism and upholding international law and human rights standards.”

U.S. refusal to arm the Syrian opposition has focused on fears that weapons could end up with Islamist extremists within the rebel ranks.

That concern was underscored Wednesday when the leader of the opposition militant group Jabhat al-Nusra issued a statement pledging allegiance to Ayman al-Zawahiri, who succeeded Osama bin Laden as head of al-Qaeda. The audio statement marked the first time that Jabhat al-Nusra has publicly acknowledged its links to al-Qaeda.

Jabhat al-Nusra, also known as the al-Nusra Front, has been among the most successful rebel groups, and its fighters have taken and held territory across northern Syria. In December, the U.S. government declared Jabhat al-Nusra a terrorist group because of its al-Qaeda ties.

But the group’s statement brought mixed reactions from Syrians who support the opposition. “Regardless of how bad the [Assad] regime can be, they are better than extremist Islamic rule,” said a 26-year-old Syrian woman who fled to Beirut from the northern city of Aleppo in February and spoke on the condition of anonymity because of security concerns.

But opposition fighters from other groups expressed admiration for Jabhat al-Nusra.

The opposition Free Syrian Army “is moderate and does not want to displease Western countries and make them afraid of supporting the Syrian revolution,” said a Free Syrian Army commander in Zabadani, Syria, who uses the nickname Abu Mazen Darkoush.

But Jabhat al-Nusra is “supported by the people because they are heroes and are ready for martyrdom,” said the commander, who has two sons fighting with the group. “They fight in the front lines and go first to death without fear.”

Gearan reported from London. Babak Dehghanpisheh in Beirut contributed to this report.