WASHINGTON — Secretary of State John Kerry told a House subcommittee Wednesday that isolating Russia could jeopardize U.S. interests in Iran and Syria, but “we will do what we have to do.”

The hearing came a day before Kerry plans to depart for London to meet with the Russian Foreign Minister Sergei Lavrov. He said it was the responsibility of the U.S. to assist Ukraine in its dispute with Russia and urged Congress to send funding for Kiev.

“We have a responsibility to be engaged, and we are engaged,” Kerry said.

The U.S. House Tuesday overwhelmingly passed a resolution supporting Ukraine and calling for sanctions against Russia for violation of the nation’s sovereignty.

Last week, the House passed legislation to provide financial assistance in Ukraine, but the funding has been held up in the Senate. Republicans are calling for an amendment dealing with a separate issue — President Barack Obama’s proposal to buckle down on tax exemptions for non-profit organizations deemed to be political in nature.

Obama issued financial sanctions against Russia Thursday, issuing an order that would freeze the assets of individuals or entities “responsible for activities undermining democratic processes or institutions in Ukraine.”

Kerry has been a key player in ongoing negotiations with Russia regarding its intervention in Crimea, a part of Ukraine with a large ethnic Russian population. At this point, Kerry said he does not believe — definitively — that Russia will annex Crimea.
The region is scheduled to hold a referendum Sunday on whether to remain in Ukraine or rejoin Russia.

On Wednesday, the U.S. in a joint statement with the other countries in the Group of 7 called the vote illegal, and promised “further action” if annexation occurs. Joined by Japan, Canada, France, Germany, Italy and Britain, the U.S. warned a referendum in Crimea would be “in violation of international law.”

Preparing for his meeting with his Russian counterpart, Kerry said it is crucial that the U.S. continue ongoing conversations with the Russian Federation.

“It can get ugly fast if the wrong decisions are made here.”

Kerry appeared before the House Appropriations subcommittee on state, foreign operations, and related programs to make a case for Obama’s 2015 budget. The budget provides $40.3 billion in discretionary funding for the State Department.

Kerry said this budget keeps the American “iron-clad” relationship with Israel intact.

“We can never eliminate every risk … but we can mitigate risks,” Kerry said.

He also responded to subcommittee Republicans’ questions’ about the planned defense reductions, including downsizing the military and the termination of several popular weapons programs.

He said a bipartisan congressional agreement easing the automatic spending cuts known as sequestration helped, but fell short of restoring the Pentagon budget to full strength.

“This is not the budget we would like to have, but this is the budget we have to have under the constraints of the budget agreement,” Kerry said.

In her opening statement, subcommittee chairwoman Rep. Kay Granger called for more funding for protection of U.S. embassies in the wake of the attacks in Benghazi, Libya.

Kerry said the budget addresses the suggestions made by the Benghazi Accountability Review Board, allocating $2.2 billion for embassy security construction.

Kerry was scheduled to appear in front of the Senate Foreign Relations Committee Wednesday afternoon, but that budget hearing was postponed. He and Obama met with Interim Ukrainian Prime Minister Arseniv Yatsenyu at the White House.