Michael Fallon urged MPs to stop criticising Saudi Arabia in the interests of securing a fighter jet deal, provoking sharp criticism from human rights and arms trade campaigners.

The defence secretary was giving evidence to the Commons defence committee, where he was pressed about why a deal to sell Typhoon fighter jets to Saudi Arabia had not yet been signed.

Fallon said he had been working extremely hard on the deal and had travelled to Jeddah in September to discuss it with his Saudi counterpart. Although Qatar had agreed two days earlier to buy 24 jets from the UK, Fallon had to settle for signing a largely meaningless joint defence agreement with the Saudis.

Fallon told the defence committee: “I have to repeat, sadly, to this committee that obviously other criticism of Saudi Arabia in this parliament is not helpful and ... I’ll leave it there,” he said. “But we need to do everything possible to encourage Saudi Arabia towards batch two. I believe they will commit to batch two.”

MPs have been outspoken in criticising Saudi Arabia over its intensive bombing campaign of Yemen which has resulted in heavy civilian casualties. Andrew Smith, spokesperson for the Campaign Against Arms Trade, said: “These comments from the secretary of state for defence are disgraceful. He is calling on other parliamentarians to join him in putting arms sales ahead of human rights, democracy and international humanitarian law.”

He added that Saudi Arabia has inflicted a terrible humanitarian catastrophe on Yemen. “Fallon should be doing all he can to stop the bloodshed and end UK complicity in the suffering, not urging his colleagues to willingly ignore the abuses in order to sell even more weapons.”

Maya Foa, director of the human rights organisation Reprieve, joined the criticism: “It is chilling that our defence secretary sees fit to warn MPs not to criticise one of the world’s worst human rights abusers. Mr Fallon must urgently explain himself to MPs and the public.”

Fallon was responding to a Labour MP, Graham Jones, who had asked about the long-term viability of BAE’s Warton and Samlesbury sites, two of the UK’s three aircraft manufacturing sites. Jones said there was uncertainty in the sector, with BAE seeking a “batch two” order of new warplanes from Saudi Arabia and asking Fallon if he was concerned that the Typhoon deal had not been secured so far.

The British government has increased the tempo of its search for arms sales around the world, seeing this as a potentially profitable niche post-Brexit. Members of the armed forces were prominently deployed in support of British arms exports at a recent arms trade fair in London.

The committee also pressed Fallon on defence spending. Big budget projects such as a replacement for the Trident nuclear weapons system and two aircraft carriers have eaten into spending for other budgets, including the army and navy.

Faced with a squeeze on the defence budget, the MoD is looking at making cuts. Fallon told the committee that since the last defence review in 2015, threats had become markedly worse and it was right the government looked afresh at its capabilities. “We have seen an extraordinary increase in Russian submarine activity over the last couple of years in the north Atlantic,” Fallon said.

“We have seen North Korea testing their missiles, we have seen cyber-attacks on our own country and on our own parliament. We have had terror attacks – five this year on our own streets.”

A Number 10 spokeswoman said the prime minister would always raise Saudi Arabia’s human rights record when speaking to her counterparts. “It’s important that we work with Saudi Arabia including co-operation on defence contracts, which are vitally important to sustain jobs here too,” she said.

“We are always clear that where we have concerns about issues such as human rights we will raise them at the highest level and we do. But Gulf security is very important to our security and it’s very important we continue to work together.”