Providing or receiving terrorist training could be outlawed under planned new anti-terror laws.
A former police chief says 3,000 Britons have gone to terror camps
New offences could cover people going to terrorist camps overseas or finding out how to build a bomb through the internet, said the Home Office.
Other proposals include making it illegal to incite terrorism indirectly by "glorifying" bombings.
The Home Office stresses the plans were in train before the London bombs. It will consult opposition MPs next week.
PLANNED NEW LAWS
Outlawing "acts preparatory to terrorism"
New offence of indirect incitement to commit terrorist acts
New law for those providing or receiving terrorist training
The new Anti-Terrorism Bill will also include introducing a new offence of "acts preparatory to terrorism".
Home Office Minister Hazel Blears said: "We want to make sure we can intervene early enough to disrupt people who are planning acts of terrorism and get convictions."
The bill is expected in the autumn and the legislation could be on the statute books by next summer.
The timetable is the same as originally planned for new anti-terror legislation before the 7 July attacks.
But ministers say they will take notice if the police and security services want the measures sooner, or if they want further powers.
Home Secretary Charles Clarke outlined details of the plans in a letter to his opposition counterparts, Conservative David Davis and Liberal Democrat Mark Oaten.
The new offence against terrorist training would cover teaching both in the UK and abroad.
Hazel Blears says the new laws could be in force next summer
It would target people "providing or receiving training in the use of hazardous substances and in other methods or techniques for terrorist purposes".
Former Metropolitan Police chief Lord Stevens has suggested 3,000 British-born or British-based people have passed through al-Qaeda training camps.
But Ms Blears said the new offence would only cover those given training in the future rather than being used retrospectively.
Catching plots early
The plan for new laws against "acts preparatory to terrorism" has been long debated.
In his letter to opposition parties, Mr Clarke said it could be used where precise details of terrorists' plans were not known or even decided by the plotters themselves.
"There may be clear evidence of an intention to commit a serious terrorist act," he said.
"For example, instructions on how to build a bomb, evidence of intention to acquire chemicals and evidence that terrorist related websites have been accessed."
But the government says that looking at terrorist-themed websites would not necessarily be a criminal act under the new training offence.
The new incitement offence could be used against extremist preachers or others making public speeches.
Inciting terrorism directly is already against the law and the new law would try to cover indirect incitement.
Ms Blears said: "It would apply where people would seek to glorify terrorist activity, perhaps, for example, saying 'isn't this a marvellous thing that this has happened' and 'these people are martyrs'."
She acknowledged there would be "intense" discussions about striking the right balance between freedom of speech and protecting the public.
Opposition parties have echoed the government's hopes of consensus on the new laws.
Conservative shadow home secretary David Davis said the plans were a "sensible start".
He supported the principle behind the plans but said the details would need to be debated to ensure effective laws.
Liberal Democrat spokesman Mark Oaten said raised concerns about the new offence of "indirect incitement to commit terrorist acts".
He said he wanted to ensure the offence could be properly defined, and was also worried about potential implications for civil liberties.
But the Lib Dems were "fully comfortable" with the other two proposed new offences, he said.
Other changes which could appear in the new bill include:
- Closing a loophole which means it is not an offence to plan an explosion overseas
- Extending terrorism stop and search powers to cover bays and estuaries
- Preventing banned organisations avoiding the rules by changing their names
- Improving search powers at ports.